Subject to Completion

Dated October 4, 2018

PRELIMINARY TERMS SUPPLEMENT

Filed Pursuant to Rule 424(b)(2)

Registration Statement No. 333-204908

Preliminary Terms Supplement

UBS AG Airbag Yield Optimization Notes

UBS AG $ Notes linked to the common stock of CenturyLink, Inc. due April 9, 2019

Indicative Terms

Issuer

UBS AG, London Branch

Issue Price per Note

Equal to 100% of the principal amount per Note.

Principal Amount per Note

$1,000

Term

Approximately 6 months.

Underlying Asset

The common stock of CenturyLink, Inc.

Coupon Payments

UBS AG will pay interest on the principal amount of the Notes on the coupon payment dates; provided that, if any coupon payment date would otherwise fall on a date which is not a business day, the relevant coupon payment date will be the first following day which is a business day unless that day falls in the next calendar month, in which case the relevant coupon payment date will be the first preceding day which is a business day. Each payment of interest due on a coupon payment date or on the maturity date, as the case may be, will include interest accrued from the last unadjusted coupon payment date on which interest has been paid or made available for payment (or the issue date in the case of the first coupon payment date) to the relevant unadjusted coupon payment date.

UBS will compute interest on the Notes on the basis of a 360-day year of twelve 30-day months. If the maturity date is postponed beyond the originally scheduled maturity date due to the occurrence of a market disruption event on the final valuation date, interest will cease to accrue on the originally scheduled maturity date. The table below reflects the coupon rate of 7% per annum. Amounts in the table below may have been rounded for ease of analysis.

Coupon Payment Date*

Coupon Payment (per Note)

November 9, 2018

0.5833%

December 10, 2018

0.5833%

January 9, 2019

0.5833%

February 11, 2019

0.5833%

March 11, 2019

0.5833%

April 9, 2019

0.5833%

*The record date for coupon payment will be one business day preceding the coupon payment date.

Coupon Rate

The Notes will bear interest at a rate of 7.00% per annum.

Total Coupon Payable

3.50%

Payment at Maturity (per Note)

If the final price of the underlying asset is equal to or greater than the conversion price, we will pay you an amount in cash at maturity equal to your principal amount.

If the final price of the underlying asset is below the conversion price, we will pay you for each Note you own an amount in cash at maturity equal to the product of (i) the final price of the underlying asset, multiplied by (ii) the share factor, subject to adjustments in the case of certain corporate events, as described in the Airbag Yield Optimization Notes product supplement. In this scenario, the cash payment you receive will be less than your principal amount and may be zero.

Closing Price

On any trading day, the last reported sale price (or, in the case of NASDAQ, the official closing price) of the underlying asset during the principal trading session on the principal national securities exchange on which it is listed for trading, as determined by the calculation agent.

Initial Price

The closing price of the underlying asset on the trade date.

Conversion Price

86.84% - 87.71% of the initial price of the underlying asset. The actual conversion price will be set when the trade is placed on the trade date. The conversion price is subject to adjustments in the case of certain corporate events, as described in the Airbag Yield Optimization Notes product supplement.

Final Price

The closing price of the underlying asset on the final valuation date. The final price is subject to adjustment in the case of certain corporate events, as described in the Airbag Yield Optimization Notes product supplement.

Share Factor

The share factor is initially set equal to (i) the principal amount divided by (ii) the conversion price of the underlying asset. The share factor will be subject to adjustments in the case of certain corporate events as described in the accompanying Airbag Yield Optimization Notes product supplement under “General Terms of the Notes - Antidilution Adjustments”.

Trade Date

October 4, 2018

Settlement Date

October 9, 2018

Final Valuation Date

April 4, 2019. The final valuation date may be subject to postponement in the event of a market disruption event, as described in the Airbag Yield Optimization Notes product supplement.

Maturity Date

April 9, 2019. The maturity date may be subject to postponement in the event of a market disruption event, as described in the Airbag Yield Optimization Notes product supplement.

CUSIP

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ISIN

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Valoren

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Tax Treatment

There is no tax authority that specifically characterizes the Notes. UBS and you agree, in the absence of an administrative determination or judicial ruling to the contrary, to characterize the Notes for tax purposes as an investment unit consisting of a non-contingent debt instrument and a put option contract in respect of the underlying asset. With respect to coupon payments you receive, you agree to treat such payments as consisting of interest on the debt component and a payment with respect to the put option as follows:

Coupon Rate

Interest on Debt

Component

Put Option Component

7.00% per annum

% per annum

% per annum

Section 871(m). A 30% withholding tax (which may be reduced by an applicable income tax treaty) is imposed on certain “dividend equivalent payments” made to a non-U.S. holder with respect to a “specified equity-linked instrument” that references one or more dividend-paying U.S. equity securities. The withholding tax can apply even if the instrument does not provide for payments that reference dividends. Treasury regulations provide that the withholding tax applies to all dividend equivalent payments made on specified equity-linked instruments issued after 2016. However, on December 2, 2016, the IRS issued Notice 2016-76, which states that the Treasury Department and the IRS intend to amend the applicability dates of the Treasury regulations to provide that the withholding tax will apply to all dividend equivalent payments made on specified equity-linked instruments that have a delta of one (“delta one specified equity-linked instruments”) issued after 2016 and to all dividend equivalent payments made on all specified equity-linked instruments issued after 2017. We have determined that the Notes are not delta one specified equity-linked instruments and, therefore, will not be subject to withholding on dividend equivalent payments. However, it is possible that the Notes could be deemed to be reissued for tax purposes upon the occurrence of certain events affecting the Notes or the underlying asset, and following such occurrence the Notes could be treated as delta one specified equity-linked instruments that are subject to withholding on dividend equivalent payments.  It is also possible that withholding tax or other Section 871(m) tax could apply to the Notes under these rules if a non-U.S. holder enters, or has entered, into certain other transactions in respect of the underlying asset or the Notes. Because of the uncertainty regarding the application of the 30% withholding tax on dividend equivalent payments to the Notes, non-U.S. holders are urged to consult their tax advisor regarding the potential application of Section 871(m) (including in the context of their other transactions in respect of the underlying asset or the Notes, if any) and the 30% withholding tax to an investment in the Notes.

For further details and possible alternative tax treatments, please refer to the section entitled "What are the Tax Consequences of the Notes" in the prospectus supplement for more information.

Offering of Notes

Issue Price to Public

Underwriting Discount

Proceeds to UBS AG

Total

Per Note

Total

Per Note

Total

Per Note

CenturyLink, Inc.

$

100%

$

1.00%

$

99.00%

UBS Financial Services Inc.

UBS Investment Bank

Additional Information About UBS and the Notes

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Prospectus Supplement dated May 2, 2016:

http://www.sec.gov/Archives/edgar/data/1114446/000119312516571261/d352822d424b2.htm

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Airbag Yield Optimization Notes product supplement dated May 2, 2016:

http://www.sec.gov/Archives/edgar/data/1114446/000119312516570611/d104496d424b2.htm

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Prospectus dated April 29, 2016:

http://www.sec.gov/Archives/edgar/data/1114446/000119312516569341/d161008d424b3.htm

Key Risks

An investment in the Notes involves significant risks. Some of the risks that apply to the Notes are summarized here and are comparable to the corresponding risks discussed in the "Key Risks" section of the prospectus supplement, but we urge you to read the more detailed explanation of risks relating to the Notes generally in the "Risk Factors" section of the Airbag Yield Optimization Notes product supplement. We also urge you to consult your investment, legal, tax, accounting and other advisors before you invest in the Notes.

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Risk of loss at maturity - The Notes differ from ordinary debt securities in that UBS will not necessarily pay the full principal amount of the Notes at maturity. UBS will only pay you the principal amount of your Notes in cash if the final price of the underlying asset is greater than or equal to the conversion price and only at maturity. If the final price of the underlying asset is below the conversion price, UBS will pay you for each Note you own an amount in cash at maturity equal to the product of (i) the final price of the underlying asset, multiplied by (ii) the share factor (subject to adjustments as described in the Airbag Yield Optimization Notes product supplement). As a result, if the final price is below the conversion price, you will be exposed at an increased rate to any such decline below the conversion price. For example, if the conversion price is 80% of the initial price, the final price is less than the conversion price and is equal to 70% of the initial price, you will lose 12.50% of your principal amount at maturity, which is greater than the 10% additional decline from the conversion price. The cash payment you receive will be less than your principal amount and may be zero.

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Higher coupon rates are generally associated with a greater risk of loss - Greater expected volatility with respect to the Note’s underlying asset reflects a higher expectation as of the trade date that the price of the underlying asset could close below its conversion price on the final valuation date of the Note. This greater expected risk will generally be reflected in a higher coupon payable on that Note. However, the underlying asset’s volatility can change significantly over the term of the Notes and the price of the underlying asset for your Note could fall sharply, which could result in a significant loss of principal.

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The contingent repayment of your principal applies only at maturity - You should be willing to hold your Notes to maturity. If you are able to sell your Notes prior to maturity in the secondary market, you may have to sell them at a loss relative to your initial investment even if the underlying asset price is above the conversion price.

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Your potential return on the Notes is limited to the coupons paid on the Notes - You will not participate in any appreciation of the underlying asset and your return on the Notes will be limited to the coupon payments. If the closing price of the underlying asset on the final valuation date is greater than or equal to the conversion price, UBS will pay you the principal amount of your Notes in cash at maturity and you will not participate in any appreciation in the price of the underlying asset even though you risked being subject to the decline in the price of the underlying asset. If the closing price of the underlying asset on the final valuation date is less than the conversion price, UBS will pay you for each Note you own an amount in cash at maturity equal to the product of (i) the final price of the underlying asset, multiplied by (ii) the share factor (subject to adjustments as described in the Airbag Yield Optimization Notes product supplement), which will be less than your principal amount and may be zero. Any payment at maturity will be unaffected by any appreciation or decline in the price of the underlying asset after the final valuation date. Therefore, your return potential on the Notes is limited to the coupons paid on the Notes and may be less than your return would be on a direct investment in the underlying asset.

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Credit risk of UBS - The Notes are unsubordinated, unsecured debt obligations of the issuer, UBS, and are not, either directly or indirectly, an obligation of any third party. Any payment to be made on the Notes, including any repayment of principal, depends on the ability of UBS to satisfy its obligations as they come due. As a result, the actual and perceived creditworthiness of UBS may affect the market value of the Notes and, in the event UBS were to default on its obligations, you may not receive any amounts owed to you under the terms of the Notes and you could lose your entire investment.

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Market risk - The price of the underlying asset can rise or fall sharply due to factors specific to that underlying asset and (i) in the case of common stock or American depositary shares, its issuer (the "underlying asset issuer") or (ii) in the case of an exchange traded fund, the securities, futures contracts or physical commodities constituting the assets of that underlying asset. These factors include price volatility, earnings, financial conditions, corporate, industry and regulatory developments, management changes and decisions and other events, as well as general market factors, such as general market volatility and levels, interest rates and economic and political conditions. You, as an investor in the Notes, should make your own investigation into the underlying asset issuer and the underlying asset for your Notes. We urge you to review financial and other information filed periodically by the underlying asset issuer with the SEC.

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Fair value considerations.

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The issue price you pay for the Notes will exceed their estimated initial value - The issue price you pay for the Notes will exceed their estimated initial value as of the trade date due to the inclusion in the issue price of the underwriting discount, hedging costs, issuance costs and projected profits. As of the close of the relevant markets on the trade date, we will determine the estimated initial value of the Notes by reference to our internal pricing models and it will be set forth in the final terms supplement. The pricing models used to determine the estimated initial value of the Notes incorporate certain variables, including the price, volatility and expected dividends on the underlying asset, prevailing interest rates, the term of the Notes and our internal funding rate. Our internal funding rate is typically lower than the rate we would pay to issue conventional fixed or floating rate debt securities of a similar term. The underwriting discount, hedging costs, issuance costs, projected profits and the difference in rates will reduce the economic value of the Notes to you. Due to these factors, the estimated initial value of the Notes as of the trade date will be less than the issue price you pay for the Notes.

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The estimated initial value is a theoretical price; the actual price that you may be able to sell your Notes in any secondary market (if any) at any time after the trade date may differ from the estimated initial value - The value of your Notes at any time will vary based on many factors, including the factors described above and in “Market risk” above and is impossible to predict. Furthermore, the pricing models that we use are proprietary and rely in part on certain assumptions about future events, which may prove to be incorrect. As a result, after the trade date, if you attempt to sell the Notes in the secondary market, the actual value you would receive may differ, perhaps materially, from the estimated initial value of the Notes determined by reference to our internal pricing models. The estimated initial value of the Notes does not represent a minimum or maximum price at which we or any of our affiliates would be willing to purchase your Notes in any secondary market at any time.

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Our actual profits may be greater or less than the differential between the estimated initial value and the issue price of the Notes as of the trade date - We may determine the economic terms of the Notes, as well as hedge our obligations, at least in part, prior to pricing the Notes on the trade date. In addition, there may be ongoing costs to us to maintain and/or adjust any hedges and such hedges are often imperfect. Therefore, our actual profits (or potentially, losses) in issuing the Notes cannot be determined as of the trade date and any such differential between the estimated initial value and the issue price of the Notes as of the trade date does not reflect our actual profits. Ultimately, our actual profits will be known only at the maturity of the Notes.

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Limited or no secondary market and secondary market price considerations.

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There may be little or no secondary market for the Notes - The Notes will not be listed or displayed on any securities exchange or any electronic communications network. There can be no assurance that a secondary market for the Notes will develop. UBS Securities LLC and its affiliates may make a market in each offering of the Notes, although they are not required to do so and may stop making a market at any time. If you are able to sell your Notes prior to maturity, you may have to sell them at a substantial loss. The estimated initial value of the Notes does not represent a minimum or maximum price at which we or any of our affiliates would be willing to purchase your Notes in any secondary market at any time.

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The price at which UBS Securities LLC and its affiliates may offer to buy the Notes in the secondary market (if any) may be greater than UBS’ valuation of the Notes at that time, greater than any other secondary market prices provided by unaffiliated dealers (if any) and, depending on your broker, greater than the valuation provided on your customer account statements - For a limited period of time following the issuance of the Notes, UBS Securities LLC or its affiliates may offer to buy or sell such Notes at a price that exceeds (i) our valuation of the Notes at that time based on our internal pricing models, (ii) any secondary market prices provided by unaffiliated dealers (if any) and (iii) depending on your broker, the valuation provided on customer account statements. The price that UBS Securities LLC may initially offer to buy such Notes following issuance will exceed the valuations indicated by our internal pricing models due to the inclusion for a limited period of time of the aggregate value of the underwriting discount, hedging costs, issuance costs and theoretical projected trading profit. The portion of such amounts included in our price will decline to zero on a straight line basis over a period ending no later than the date specified under “Supplemental Plan of Distribution (Conflicts of Interest); Secondary Markets (if any).” Thereafter, if UBS Securities LLC or an affiliate makes secondary markets for the Notes, it will do so at prices that reflect our estimated value determined by reference to our internal pricing models at that time. The temporary positive differential relative to our internal pricing models arises from requests from and arrangements made by UBS Securities LLC with the selling agents of structured debt securities such as the Notes. As described above, UBS Securities LLC and its affiliates are not required to make a market for the Notes and may stop making a market at any time. The price at which UBS Securities LLC or an affiliate may make secondary markets at any time (if at all) will also reflect its then current bid-ask spread for similar sized trades of structured debt securities. UBS Financial Services Inc. and UBS Securities LLC reflect this temporary positive differential on their customer statements. Investors should inquire as to the valuation provided on customer account statements provided by unaffiliated dealers.

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Price of Notes prior to maturity - The market price of the Notes will be influenced by many unpredictable and interrelated factors, including the price of the underlying asset; the volatility of the underlying asset; the dividend rate paid on the underlying asset; the time remaining to the maturity of the Notes; interest rates in the markets; geopolitical conditions and economic, financial, political, force majeure and regulatory or judicial events; the creditworthiness of UBS and the then current bid-ask spread for the Notes.

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Impact of fees and the use of internal funding rates rather than secondary market credit spreads on secondary market prices - All other things being equal, the use of the internal funding rates described above under “- Fair value considerations” as well as the inclusion in the issue price of the underwriting discount, hedging costs, issuance costs and any projected profits are, subject to the temporary mitigating effect of UBS Securities LLC’s and its affiliates’ market making premium, expected to reduce the price at which you may be able to sell the Notes in any secondary market.

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Owning the Notes is not the same as owning the underlying asset - The return on your Notes may not reflect the return you would realize if you actually owned the underlying asset. For instance, you will not receive or be entitled to receive any dividend payments or other distributions on the underlying asset, and you will not participate in any appreciation of the underlying asset, over the term of the Notes.

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No assurance that the investment view implicit in the Notes will be successful - It is impossible to predict whether and the extent to which the price of the underlying asset will rise or fall. There can be no assurance that the underlying asset price will not rise by more than the coupons paid on the Notes or will not close below the conversion price on the final valuation date. The price of the underlying asset will be influenced by complex and interrelated political, economic, financial and other factors that affect the issuer of the underlying asset or, for Notes linked to exchange traded funds, the underlying asset constituent stock issuers. You should be willing to accept the risks of owning equities in general and the underlying asset in particular, and the risk of losing some or all of your initial investment.

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The calculation agent can make adjustments that affect the payment to you at maturity - The calculation agent may adjust the amount payable at maturity by adjusting the conversion price, the share factor and/or the final price for certain corporate events affecting the underlying asset, such as stock splits and stock dividends, and certain other actions involving the underlying asset. However, the calculation agent is not required to make an adjustment for every corporate event that can affect the underlying asset. If an event occurs that does not require the calculation agent to adjust the conversion price and the share factor, the market value of your Notes and the payment at maturity may be materially and adversely affected. In the case of common stock or American depositary shares, following certain corporate events relating to the issuer of the underlying asset where the issuer is not the surviving entity, the amount of cash you receive at maturity may be based on the common stock or American depositary shares of a successor to the underlying asset issuer in combination with any cash or any other assets distributed to holders of the underlying asset in such corporate event. Additionally, if the issuer of the underlying asset becomes subject to (i) a reorganization event whereby the underlying asset is exchanged solely for cash, (ii) a merger or consolidation with UBS or any of its affiliates or (iii) an underlying equity is delisted or otherwise suspended from trading, the amount you receive at maturity may be based on the common stock or American depositary shares issued by another company. In the case of an exchange traded fund, following a suspension from trading or if an exchange traded fund is discontinued, the amount you receive at maturity may be based on a share of another exchange traded fund. The occurrence of these corporate events and the consequent adjustments may materially and adversely affect the value of the Notes. For more information, see the section “General Terms of the Notes - Antidilution Adjustments” beginning on page PS-32 of the Airbag Yield Optimization Notes product supplement. Regardless of the occurrence of one or more dilution or reorganization events, you should note that at maturity UBS will pay you an amount in cash equal to your principal amount, unless the final price of the underlying asset is below the conversion price (as such conversion price may be adjusted by the calculation agent upon theoccurrence of one or more such events). Regardless of any of the events discussed above, any payment on the Notes is subject to the creditworthiness of UBS.

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There is no affiliation between the underlying asset issuer, or for Notes linked to exchange traded funds, the issuers of the constituent stocks comprising the underlying asset (the "underlying asset constituent stock issuers"), and UBS, and UBS is not responsible for any disclosure by such issuer(s) - We and our affiliates may currently, or from time to time in the future engage in business with the underlying asset issuer or, if applicable, any underlying asset constituent stock issuers. However, we are not affiliated with the underlying asset issuer or any underlying asset constituent stock issuers and are not responsible for such issuer's public disclosure of information, whether contained in SEC filings or otherwise. You, as an investor in the Notes, should make your own investigation into the underlying asset issuer or, if applicable, each underlying asset constituent stock issuer. Neither the underlying asset issuer nor any underlying asset constituent stock issuer is involved in the Notes offered hereby in any way and has no obligation of any sort with respect to your Notes. Such issuer(s) have no obligation to take your interests into consideration for any reason, including when taking any corporate actions that might affect the value of your Notes.

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Potential UBS impact on the market price of the underlying asset - Trading or transactions by UBS or its affiliates in the underlying asset and/or over-the-counter options, futures or other instruments with returns linked to the performance of the underlying asset may adversely affect the market price of the underlying asset and, therefore, the market value of your Notes.

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Potential conflict of interest - UBS and its affiliates may engage in business with the issuer of the underlying asset or, for Notes linked to exchange traded funds, the underlying asset constituent stock issuers, which may present a conflict between the obligations of UBS and you, as a holder of the Notes. The calculation agent, an affiliate of UBS, will determine whether the final price is below the conversion price and accordingly the payment at maturity on your Notes. The calculation agent may also postpone the determination of the final price and the maturity date if a market disruption event occurs and is continuing on the final valuation date and may make adjustments to the share factor, conversion price, the final price and/or the underlying asset itself for certain corporate events affecting the underlying asset. For more information, see the section “General Terms of the Notes — Antidilution Adjustments” beginning on page PS-32 of the Airbag Yield Optimization Notes product supplement. As UBS determines the economic terms of the Notes, including the coupon rate and conversion price, and such terms include hedging costs, issuance costs and projected profits, the Notes represent a package of economic terms. There are other potential conflicts of interest insofar as an investor could potentially get better economic terms if that investor entered into exchange-traded and/or OTC derivatives or other instruments with third parties, assuming that such instruments were available and the investor had the ability to assemble and enter into such instruments.

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Potentially inconsistent research, opinions or recommendations by UBS - UBS and its affiliates may publish research or express opinions or provide recommendations that are inconsistent with purchasing or holding the Notes, and which may be revised without notice. Any research, opinions or recommendations expressed by UBS or its affiliates may not be consistent with each other and may influence the value of the Notes.

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The Notes are not bank deposits: An investment in the Notes carries risks which are very different from the risk profile of a bank deposit placed with UBS or its affiliates. The Notes have different yield and/or return, liquidity and risk profiles and would not benefit from any protection provided to deposits.

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Under certain circumstances, the Swiss Financial Market Supervisory Authority (FINMA) has the power to take actions that may adversely affect the Notes - Pursuant to article 25 et seq. of the Swiss Banking Act, FINMA has broad statutory powers to take measures and actions in relation to UBS if it (i) is overindebted, (ii) has serious liquidity problems or (iii) fails to fulfill the applicable capital adequacy provisions after expiration of a deadline set by FINMA. If one of these prerequisites is met, the Swiss Banking Act grants significant discretion to FINMA to open restructuring proceedings or liquidation (bankruptcy) proceedings in respect of, and/or impose protective measures in relation to, UBS. In particular, a broad variety of protective measures may be imposed by FINMA, including a bank moratorium or a maturity postponement, which measures may be ordered by FINMA either on a stand-alone basis or in connection with restructuring or liquidation proceedings. In a restructuring proceeding, the resolution plan may, among other things, (a) provide for the transfer of UBS's assets or a portion thereof, together with debts and other liabilities, and contracts of UBS, to another entity, (b) provide for the conversion of UBS's debt and/or other obligations, including its obligations under the Notes, into equity, and/or (c) potentially provide for haircuts on obligations of UBS, including its obligations under the Notes. Although no precedent exists, if one or more measures under the revised regime were imposed, such measures may have a material adverse effect on the terms and market value of the Notes and/or the ability of UBS to make payments thereunder.

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Dealer incentives - UBS and its affiliates may act as a principal, agent or dealer in connection with the sale of the Notes. Such affiliates, including the sales representatives, will derive compensation from the distribution of the Notes which may serve as an incentive to sell these Notes instead of other investments. We will pay total underwriting compensation of 1.0% per Note to any of our affiliates acting as agents or dealers in connection with the distribution of the Notes. Given that UBS Securities LLC and its affiliates temporarily maintain a market making premium, it may have the effect of discouraging UBS Securities LLC and its affiliates from recommending sale of your Notes in the secondary market.

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Uncertain tax treatment - Significant aspects of the tax treatment of the Notes are uncertain. You should read carefully the sections entitled "What are the Tax Consequences of the Notes?" in the prospectus supplement and “Supplemental U.S. Tax Considerations ” beginning on page PS-46 of the Airbag Yield Optimization Notes product supplement and consult your tax advisor about your tax situation.

Information about the Underlying Asset

All disclosures regarding the underlying asset are derived from publicly available information. UBS has not conducted any independent review or due diligence of any publicly available information with respect to the underlying asset. You should make your own investigation into the underlying asset.

The underlying asset will be registered under the Securities Exchange Act of 1934, as amended (the "Exchange Act"). Companies with securities registered under the Exchange Act are required to file financial and other information specified by the SEC periodically. Information filed by the issuer of the underlying asset with the SEC can be reviewed electronically through a website maintained by the SEC. The address of the SEC’s website is http://www.sec.gov. Information filed with the SEC by the issuer of the underlying asset under the Exchange Act can be located by reference to its SEC file number provided below. In addition, information filed with the SEC can be inspected and copied at the Public Reference Section of the SEC, 100 F Street, N.E., Room 1580, Washington, D.C. 20549. Copies of this material can also be obtained from the Public Reference Section, at prescribed rates.

CenturyLink, Inc.

Quarter Begin

Quarter End

Quarterly High

Quarterly Low

Quarterly Close

01/02/2014

03/31/2014

$32.84

$28.09

$32.84

04/01/2014

06/30/2014

$38.18

$33.08

$36.20

07/01/2014

09/30/2014

$41.47

$35.94

$40.89

10/01/2014

12/31/2014

$41.81

$37.58

$39.58

01/02/2015

03/31/2015

$40.52

$34.06

$34.55

04/01/2015

06/30/2015

$36.78

$29.38

$29.38

07/01/2015

09/30/2015

$30.94

$24.61

$25.12

10/01/2015

12/31/2015

$28.81

$24.38

$25.16

01/04/2016

03/31/2016

$32.17

$22.24

$31.96

04/01/2016

06/30/2016

$32.80

$26.63

$29.01

07/01/2016

09/30/2016

$31.44

$26.75

$27.43

10/03/2016

12/30/2016

$31.00

$23.00

$23.78

01/03/2017

03/31/2017

$26.06

$22.45

$23.57

04/03/2017

06/30/2017

$27.31

$23.60

$23.88

07/03/2017

09/29/2017

$23.97

$18.32

$18.90

10/02/2017

12/29/2017

$20.35

$13.62

$16.68

01/02/2018

03/29/2018

$19.13

$15.52

$16.43

04/02/2018

06/29/2018

$19.60

$16.29

$18.64

07/02/2018

09/28/2018

$23.98

$18.26

$21.20

10/01/2018*

10/03/2018*

$21.89

$21.45

$21.89

Supplemental Plan of Distribution (Conflicts of Interest); Secondary Markets (if any)

We will agree to sell to UBS Securities LLC and UBS Securities LLC will agree to purchase, all of the Notes at the issue price to the public less the underwriting discount indicated on the cover of the final terms supplement, the document that will be filed pursuant to Rule 424(b) containing the final pricing terms of the Notes. UBS Securities LLC will agree to resell all of the Notes to UBS Financial Services Inc. at a discount from the issue price to the public equal to the underwriting discount indicated on the cover of the final terms supplement.

Conflicts of Interest - Each of UBS Securities LLC and UBS Financial Services Inc. is an affiliate of UBS and, as such, has a "conflict of interest" in this offering within the meaning of FINRA Rule 5121. In addition, UBS will receive the net proceeds (excluding the underwriting discount) from the initial public offering of the Notes and, thus creates an additional conflict of interest within the meaning of FINRA Rule 5121. Consequently, the offering is being conducted in compliance with the provisions of Rule 5121. Neither UBS Securities LLC nor UBS Financial Services Inc. is permitted to sell Notes in the offering to an account over which it exercises discretionary authority without the prior specific written approval of the account holder.

UBS Securities LLC and its affiliates may offer to buy or sell the Notes in the secondary market (if any) at prices greater than UBS’ internal valuation - The value of the Notes at any time will vary based on many factors that cannot be predicted. However, the price (not including UBS Securities LLC’s or any affiliate’s customary bid-ask spreads) at which UBS Securities LLC or any affiliate would offer to buy or sell the Notes immediately after the trade date in the secondary market is expected to exceed the estimated initial value of the Notes as determined by reference to our internal pricing models. The amount of the excess will decline to zero on a straight line basis over a period ending no later than 1 month after the trade date, provided that UBS Securities LLC may shorten the period based on various factors, including the magnitude of purchases and other negotiated provisions with selling agents. Notwithstanding the foregoing, UBS Securities LLC and its affiliates are not required to make a market for the Notes and may stop making a market at any time. For more information about secondary market offers and the estimated initial value of the Notes, see “Key Risks - Fair value considerations” and “Key Risks - Limited or no secondary market and secondary market price considerations” on pages 4 and 5 of this preliminary terms supplement.

Prohibition of Sales to EEA Retail Investors — The Notes are not intended to be offered, sold or otherwise made available to and should not be offered, sold or otherwise made available to any retail investor in the European Economic Area (“EEA”). For these purposes, a retail investor means a person who is one (or more) of: (i) a retail client as defined in point (11) of Article 4(1) of Directive 2014/65/EU, as amended (“MiFID II”); (ii) a customer within the meaning of Directive 2002/92/EC, as amended, where that customer would not qualify as a professional client as defined in point (10) of Article 4(1) of MiFID II; or (iii) not a qualified investor as defined in Directive 2003/71/EC, as amended. Consequently no key information document required by Regulation (EU) No 1286/2014 (as amended, the “PRIIPs Regulation”) for offering or selling the Notes or otherwise making them available to retail investors in the EEA has been prepared and therefore offering or selling the Notes or otherwise making them available to any retail investor in the EEA may be unlawful under the PRIIPs Regulation.

You should rely only on the information incorporated by reference or provided in this preliminary terms supplement, the accompanying prospectus supplement, the product supplement or the accompanying prospectus. We have not authorized anyone to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this preliminary terms supplement is accurate as of any date other than the date on the front of the document.

TABLE OF CONTENTS

Preliminary Terms Supplement

Use of Proceeds

12

Description of Debt Securities We May Offer

13

Description of Warrants We May Offer

33

Legal Ownership and Book-Entry Issuance

48

Considerations Relating to Indexed Securities

53

Considerations Relating to Securities Denominated or Payable in or Linked to a Non-U.S. Dollar Currency

56

U.S. Tax Considerations

59

Tax Considerations Under the Laws of Switzerland

70

Benefit Plan Investor Considerations

72

Plan of Distribution

74

Indicative Terms

1

Conflicts of Interest

76

Additional Information About UBS and the Notes

3

Validity of the Securities

77

Key Risks

4

Experts

77

Information About the Underlying Asset

7

$ •

UBS AG Airbag Yield Optimization Notes due on or about April 9, 2019

Preliminary Terms Supplement dated October 4, 2018

(To Prospectus Supplement dated May 2, 2016,

Product Supplement dated May 2, 2016 and

Prospectus dated April 29, 2016)

UBS Investment Bank

UBS Financial Services Inc.

CenturyLink, Inc.

7

Supplemental Plan of Distribution (Conflicts of Interest); Secondary Markets (if any)

9

Prospectus Supplement

Investment Description

i

Features

i

Note Offering

i

Additional Information About UBS and the Notes

ii

Investor Suitability

1

Summary Terms

2

Investment Timeline

2

What are the Tax Consequences of the Notes ?

3

Key Risks

6

Hypothetical Examples and Return Table

11

Information About the Underlying Asset

13

Supplemental Plan of Distribution (Conflicts of Interest); Secondary Markets (if any)

13

Annex A – Form of Final Terms Supplement

A-2

Annex B – UBS Equity Investor - Investment Guide

B-2

Product Supplement

Product Supplement Summary

PS-1

Hypothetical Payment Amounts on Your Notes

PS-13

Risk Factors

PS-14

General Terms of the Notes

PS-28

Use of Proceeds and Hedging

PS-46

Supplemental U.S. Tax Considerations

PS-47

Certain ERISA Considerations

PS-55

Supplemental Plan of Distribution (Conflicts of Interest)

PS-56

Prospectus

Introduction

1

Cautionary Note Regarding Forward-Looking Statements

4

Incorporation of Information About UBS AG

5

Where You Can Find More Information

6

Presentation of Financial Information

7

Limitations on Enforcement of U.S. Laws Against UBS AG, Its Management and Others

7

UBS

8

Swiss Regulatory Powers

11