UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549

FORM N-Q

QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED MANAGEMENT INVESTMENT COMPANY
 
Investment Company Act file number 811-06548
 
Nuveen Select Tax-Free Income Portfolio
(Exact name of registrant as specified in charter)
 
Nuveen Investments
        333 West Wacker Drive, Chicago, Illinois 60606         
(Address of principal executive offices) (Zip code)
 

Kevin J. McCarthy
Vice President and Secretary
        333 West Wacker Drive, Chicago, Illinois 60606         
(Name and address of agent for service)
 
Registrant's telephone number, including area code:         312-917-7700        
 
Date of fiscal year end:            3/31          
 
Date of reporting period:         6/30/16         
 
Form N-Q is to be used by management investment companies, other than small business investment companies registered on Form N-5 (§§ 239.24 and 274.5 of this chapter), to file reports with the Commission, not later than 60 days after the close of the first and third fiscal quarters, pursuant to rule 30b1-5 under the Investment Company Act of 1940 (17 CFR 270.30b1-5). The Commission may use the information provided on Form N-Q in its regulatory, disclosure review, inspection, and policymaking roles.
 
A registrant is required to disclose the information specified by Form N-Q, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-Q unless the Form displays a currently valid Office of Management and Budget ("OMB") control number. Please direct comments concerning the accuracy of the information collection burden estimate and any suggestions for reducing the burden to the Secretary, Securities and Exchange Commission, 450 Fifth Street, NW, Washington, DC 20549-0609. The OMB has reviewed this collection of information under the clearance requirements of 44 U.S.C. § 3507.

 
 
Item 1. Schedule of Investments
 

 
  
Portfolio of Investments 
 
 
 
           
 
  
Nuveen Select Tax-Free Income Portfolio (NXP) 
 
 
 
 
  
June 30, 2016 (Unaudited) 
 
 
 
 
 
Principal 
  
 
Optional Call 
 
 
Amount (000) 
  
Description (1) 
Provisions (2) 
Ratings (3) 
Value 
 
  
LONG-TERM INVESTMENTS – 101.9% 
 
 
 
           
 
  
MUNICIPAL BONDS – 101.9% 
 
 
 
           
 
  
Alaska – 1.0% 
 
 
 
$ 2,675 
  
Northern Tobacco Securitization Corporation, Alaska, Tobacco Settlement Asset-Backed Bonds, 
12/16 at 100.00 
B3 
$ 2,648,250 
 
  
Series 2006A, 5.000%, 6/01/46 
 
 
 
 
  
Arizona – 2.4% 
 
 
 
2,500 
  
Arizona Health Facilities Authority, Hospital Revenue Bonds, Catholic Healthcare West, Series 
3/21 at 100.00 
A 
2,850,250 
 
  
2011B-1&2, 5.250%, 3/01/39 
 
 
 
2,530 
  
Arizona Water Infrastructure Finance Authority, Water Quality Revenue Bonds, Series 2008A, 
10/18 at 100.00 
AAA 
2,775,714 
 
  
5.000%, 10/01/20 
 
 
 
625 
  
Pima County Industrial Development Authority, Arizona, Revenue Bonds, Tucson Electric Power 
10/20 at 100.00 
A3 
706,906 
 
  
Company, Series 2010A, 5.250%, 10/01/40 
 
 
 
5,655 
  
Total Arizona 
 
 
6,332,870 
 
  
Arkansas – 0.9% 
 
 
 
6,555 
  
Arkansas Development Finance Authority, Tobacco Settlement Revenue Bonds, Arkansas Cancer 
No Opt. Call 
Aa2 
2,359,341 
 
  
Research Center Project, Series 2006, 0.000%, 7/01/46 – AMBAC Insured 
 
 
 
 
  
California – 19.5% 
 
 
 
2,000 
  
Alameda Corridor Transportation Authority, California, Revenue Bonds, Refunding Subordinate 
10/17 at 100.00 
BBB+ (4) 
2,122,560 
 
  
Lien Series 2004A, 5.450%, 10/01/25 (Pre-refunded 10/01/17) – AMBAC Insured 
 
 
 
4,245 
  
Anaheim City School District, Orange County, California, General Obligation Bonds, Election 
No Opt. Call 
AA 
2,796,860 
 
  
2002 Series 2007, 0.000%, 8/01/31 – AGM Insured 
 
 
 
2,840 
  
Anaheim Public Financing Authority, California, Lease Revenue Bonds, Public Improvement 
No Opt. Call 
AA 
1,865,454 
 
  
Project, Series 1997C, 0.000%, 9/01/30 – AGM Insured 
 
 
 
3,000 
  
Bay Area Toll Authority, California, Revenue Bonds, San Francisco Bay Area Toll Bridge, Series 
4/23 at 100.00 
AA– 
3,626,850 
 
  
2013S-4, 5.000%, 4/01/38 
 
 
 
2,310 
  
California Health Facilities Financing Authority, Revenue Bonds, Saint Joseph Health System, 
7/23 at 100.00 
AA– 
2,797,687 
 
  
Series 2013A, 5.000%, 7/01/33 
 
 
 
1,630 
  
California State Public Works Board, Lease Revenue Bonds, Various Capital Projects, Series 
11/23 at 100.00 
A+ 
1,980,678 
 
  
2013I, 5.000%, 11/01/38 
 
 
 
1,500 
  
California Statewide Community Development Authority, Health Revenue Bonds, Enloe Medical 
8/18 at 100.00 
AA– (4) 
1,679,265 
 
  
Center, Refunding Series 2008A, 6.250%, 8/15/28 (Pre-refunded 8/15/18) 
 
 
 
895 
  
California Statewide Community Development Authority, Revenue Bonds, Methodist Hospital 
8/19 at 100.00 
N/R (4) 
1,061,023 
 
  
Project, Series 2009, 6.750%, 2/01/38 (Pre-refunded 8/01/19) 
 
 
 
3,790 
  
Coast Community College District, Orange County, California, General Obligation Bonds, Series 
8/16 at 33.78 
Aa1 (4) 
1,279,920 
 
  
2006C, 0.000%, 8/01/36 (Pre-refunded 8/01/16) – AGM Insured 
 
 
 
2,645 
  
Cypress Elementary School District, Orange County, California, General Obligation Bonds, 
No Opt. Call 
AA 
1,566,105 
 
  
Series 2009A, 0.000%, 5/01/34 – AGM Insured 
 
 
 
800 
  
East Side Union High School District, Santa Clara County, California, General Obligation 
8/19 at 100.00 
AA (4) 
905,968 
 
  
Bonds, 2008 Election Series 2010B, 5.000%, 8/01/24 (Pre-refunded 8/01/19) – AGC Insured 
 
 
 
2,710 
  
Golden State Tobacco Securitization Corporation, California, Enhanced Tobacco Settlement 
No Opt. Call 
A+ 
2,050,900 
 
  
Asset-Backed Revenue Bonds, Series 2005A, 0.000%, 6/01/28 – AMBAC Insured 
 
 
 
1,395 
  
Golden State Tobacco Securitization Corporation, California, Tobacco Settlement Asset-Backed 
6/17 at 100.00 
B 
1,420,890 
 
  
Bonds, Series 2007A-1, 4.500%, 6/01/27 
 
 
 
2,350 
  
Golden Valley Unified School District, Madera County, California, General Obligation Bonds, 
8/17 at 56.07 
AA 
1,302,041 
 
  
Election 2006 Series 2007A, 0.000%, 8/01/29 – AGM Insured 
 
 
 
3,030 
  
Grossmont Union High School District, San Diego County, California, General Obligation Bonds, 
No Opt. Call 
Aa3 
2,535,656 
 
  
Series 2006, 0.000%, 8/01/25 – NPFG Insured 
 
 
 
1,000 
  
Moreno Valley Unified School District, Riverside County, California, General Obligation Bonds, 
No Opt. Call 
AA– 
869,290 
 
  
Series 2007, 0.000%, 8/01/23 – NPFG Insured 
 
 
 
1,160 
  
Mount San Antonio Community College District, Los Angeles County, California, General 
8/35 at 100.00 
AA 
1,020,290 
 
  
Obligation Bonds, Election of 2008, Series 2013A, 0.000%, 8/01/43 (5) 
 
 
 
5,395 
  
Napa Valley Community College District, Napa and Sonoma Counties, California, General 
8/17 at 46.57 
Aa2 
2,480,459 
 
  
Obligation Bonds, Election 2002 Series 2007C, 0.000%, 8/01/32 – NPFG Insured 
 
 
 
2,180 
  
New Haven Unified School District, Alameda County, California, General Obligation Bonds, 
No Opt. Call 
AA– 
1,215,350 
 
  
Series 2004A, 0.000%, 8/01/28 – NPFG Insured 
 
 
 
590 
  
Palomar Pomerado Health Care District, California, Certificates of Participation, Series 2009, 
11/19 at 100.00 
Ba1 
663,007 
 
  
6.750%, 11/01/39 
 
 
 
4,390 
  
Pittsburg Redevelopment Agency, California, Tax Allocation Bonds, Los Medanos Community 
No Opt. Call 
A+ 
3,061,849 
 
  
Development Project, Series 1999, 0.000%, 8/01/29 – AMBAC Insured 
 
 
 
1,700 
  
Placentia-Yorba Linda Unified School District, Orange County, California, Certificates of 
No Opt. Call 
AA– (4) 
1,183,285 
 
  
Participation, Series 2006, 0.000%, 10/01/34 – NPFG Insured (ETM) 
 
 
 
8,000 
  
Poway Unified School District, San Diego County, California, General Obligation Bonds, School 
No Opt. Call 
AA– 
5,004,080 
 
  
Facilities Improvement District 2007-1, Election 2008 Series 2009A, 0.000%, 8/01/33 
 
 
 
3,420 
  
San Diego County Water Authority, California, Water Revenue Certificates of Participation, 
5/18 at 100.00 
AAA 
3,696,883 
 
  
Series 2008A, 5.000%, 5/01/38 (Pre-refunded 5/01/18) (WI/DD, Settling 7/01/16) – AGM Insured 
 
 
 
2,110 
  
Sierra Sands Unified School District, Kern County, California, General Obligation Bonds, 
No Opt. Call 
AA 
1,528,611 
 
  
Election of 2006, Series 2006A, 0.000%, 11/01/28 – FGIC Insured 
 
 
 
1,195 
  
Tobacco Securitization Authority of Northern California, Tobacco Settlement Asset-Backed 
12/16 at 100.00 
B– 
1,195,084 
 
  
Bonds, Series 2005A-1, 5.500%, 6/01/45 
 
 
 
1,150 
  
Woodside Elementary School District, San Mateo County, California, General Obligation Bonds, 
No Opt. Call 
AAA 
797,468 
 
  
Election of 2005, Series 2007, 0.000%, 10/01/30 – AMBAC Insured 
 
 
 
67,430 
  
Total California 
 
 
51,707,513 
 
  
Colorado – 4.6% 
 
 
 
1,780 
  
Colorado Health Facilities Authority, Colorado, Revenue Bonds, Catholic Health Initiatives, 
1/23 at 100.00 
A+ 
2,056,505 
 
  
Series 2013A, 5.250%, 1/01/45 
 
 
 
1,000 
  
Colorado Health Facilities Authority, Colorado, Revenue Bonds, Sisters of Charity of 
1/20 at 100.00 
AA– 
1,120,450 
 
  
Leavenworth Health Services Corporation, Series 2010A, 5.000%, 1/01/40 
 
 
 
1,935 
  
Denver City and County, Colorado, Airport System Revenue Bonds, Subordinate Lien Series 2013B, 
11/23 at 100.00 
A 
2,290,382 
 
  
5.000%, 11/15/43 
 
 
 
250 
  
E-470 Public Highway Authority, Colorado, Senior Revenue Bonds, Series 2000B, 0.000%, 
No Opt. Call 
AA– 
175,495 
 
  
9/01/29 – NPFG Insured 
 
 
 
12,500 
  
E-470 Public Highway Authority, Colorado, Senior Revenue Bonds, Series 2006A, 0.000%, 
9/26 at 54.77 
AA– 
4,895,875 
 
  
9/01/38 – NPFG Insured 
 
 
 
2,000 
  
E-470 Public Highway Authority, Colorado, Toll Revenue Bonds, Series 2004B, 0.000%, 
9/20 at 50.83 
AA– 
890,660 
 
  
9/01/32 – NPFG Insured 
 
 
 
620 
  
Park Creek Metropolitan District, Colorado, Senior Limited Property Tax Supported Revenue 
12/25 at 100.00 
BBB 
740,168 
 
  
Bonds, Refunding Series 2015A, 5.000%, 12/01/35 
 
 
 
20,085 
  
Total Colorado 
 
 
12,169,535 
 
  
Florida – 4.6% 
 
 
 
2,990 
  
Duval County School Board, Florida, Certificates of Participation, Master Lease Program, 
7/17 at 100.00 
Aa3 (4) 
3,123,324 
 
  
Series 2008, 5.000%, 7/01/26 (Pre-refunded 7/01/17) – AGM Insured 
 
 
 
2,000 
  
Florida State Turnpike Authority, Turnpike Revenue Bonds, Department of Transportation, Series 
No Opt. Call 
Aa2 
2,000,260 
 
  
2010B, 5.000%, 7/01/16 
 
 
 
2,500 
  
JEA St. Johns River Power Park System, Florida, Revenue Bonds, 2012-Issue 2 Series 25, 
No Opt. Call 
Aa2 
2,528,825 
 
  
5.000%, 10/01/16 
 
 
 
4,240 
  
Miami-Dade County, Florida, Special Obligation Bonds, Capital Asset Acquisition, Series 2007A, 
4/17 at 100.00 
AA– 
4,377,588 
 
  
5.000%, 4/01/23 – AMBAC Insured 
 
 
 
11,730 
  
Total Florida 
 
 
12,029,997 
 
  
Illinois – 10.8% 
 
 
 
 
  
Board of Trustees of Southern Illinois University, Housing and Auxiliary Facilities System 
 
 
 
 
  
Revenue Bonds, Series 1999A: 
 
 
 
2,565 
  
0.000%, 4/01/20 – NPFG Insured 
No Opt. Call 
AA– 
2,320,479 
2,000 
  
0.000%, 4/01/23 – NPFG Insured 
No Opt. Call 
AA– 
1,631,900 
735 
  
Chicago Board of Education, Illinois, General Obligation Bonds, Dedicated Revenues Series 
12/21 at 100.00 
B+ 
654,077 
 
  
2011A, 5.000%, 12/01/41 
 
 
 
55 
  
Chicago Board of Education, Illinois, Unlimited Tax General Obligation Bonds, Dedicated Tax 
No Opt. Call 
AA– 
33,686 
 
  
Revenues, Series 1998B-1, 0.000%, 12/01/28 – FGIC Insured 
 
 
 
1,370 
  
Chicago, Illinois, General Airport Revenue Bonds, O’Hare International Airport, Third Lien 
1/17 at 100.00 
AA 
1,400,003 
 
  
Series 2008B, 5.000%, 1/01/20 – AGM Insured 
 
 
 
2,100 
  
Illinois Finance Authority, Revenue Bonds, Northwestern Memorial HealthCare, Series 2013, 
No Opt. Call 
AA+ 
2,320,520 
 
  
4.000%, 8/15/33 
 
 
 
260 
  
Illinois Finance Authority, Revenue Bonds, Rehabilitation Institute of Chicago, Series 2013A, 
7/23 at 100.00 
A– 
321,610 
 
  
6.000%, 7/01/43 
 
 
 
2,100 
  
Illinois Finance Authority, Revenue Bonds, Silver Cross Hospital and Medical Centers, 
8/18 at 100.00 
BBB+ 
2,241,456 
 
  
Refunding Series 2008A, 5.500%, 8/15/30 
 
 
 
1,000 
  
Illinois Finance Authority, Revenue Bonds, Silver Cross Hospital and Medical Centers, Series 
8/19 at 100.00 
N/R (4) 
1,186,520 
 
  
2009, 6.875%, 8/15/38 (Pre-refunded 8/15/19) 
 
 
 
1,050 
  
Illinois Finance Authority, Revenue Bonds, University of Chicago, Tender Option Bond Trust 
No Opt. Call 
AA+ (4) 
1,142,789 
 
  
2015-XF0248, 8.984%, 7/01/46 (Pre-refunded 7/01/17) (IF) (6) 
 
 
 
2,190 
  
Illinois State, General Obligation Bonds, Refunding Series 2012, 5.000%, 8/01/23 
No Opt. Call 
BBB+ 
2,480,131 
1,000 
  
Kendall, Kane, and Will Counties Community Unit School District 308 Oswego, Illinois, General 
No Opt. Call 
Aa2 
828,830 
 
  
Obligation Bonds, Series 2008, 0.000%, 2/01/24 – AGM Insured 
 
 
 
1,520 
  
Metropolitan Pier and Exposition Authority, Illinois, Revenue Bonds, McCormick Place Expansion 
No Opt. Call 
AA– 
1,501,669 
 
  
Project, Series 1993A, 0.000%, 6/15/17 – NPFG Insured 
 
 
 
470 
  
Metropolitan Pier and Exposition Authority, Illinois, Revenue Bonds, McCormick Place Expansion 
No Opt. Call 
AA– (4) 
466,489 
 
  
Project, Series 1993A, 0.000%, 6/15/17 – NPFG Insured (ETM) 
 
 
 
 
  
Metropolitan Pier and Exposition Authority, Illinois, Revenue Bonds, McCormick Place Expansion 
 
 
 
 
  
Project, Series 2002A: 
 
 
 
1,720 
  
0.000%, 12/15/29 – NPFG Insured 
No Opt. Call 
AA– 
1,112,530 
810 
  
0.000%, 6/15/30 – NPFG Insured 
No Opt. Call 
AA– 
509,085 
6,070 
  
0.000%, 12/15/31 – NPFG Insured 
No Opt. Call 
AA– 
3,607,280 
5,000 
  
0.000%, 12/15/36 – NPFG Insured 
No Opt. Call 
AA– 
2,373,600 
1,775 
  
Springfield, Illinois, Electric Revenue Bonds, Senior Lien Series 2015, 5.000%, 3/01/28 
3/25 at 100.00 
A 
2,188,930 
310 
  
University of Illinois, Health Services Facilities System Revenue Bonds, Series 2013, 
10/23 at 100.00 
A 
380,742 
 
  
6.000%, 10/01/42 
 
 
 
34,100 
  
Total Illinois 
 
 
28,702,326 
 
  
Indiana – 0.8% 
 
 
 
270 
  
Indiana Finance Authority, Tax-Exempt Private Activity Revenue Bonds, I-69 Section 5 Project, 
9/24 at 100.00 
BBB– 
308,667 
 
  
Series 2014, 5.250%, 9/01/34 (Alternative Minimum Tax) 
 
 
 
485 
  
Indiana Health Facility Financing Authority, Revenue Bonds, Community Foundation of Northwest 
3/17 at 100.00 
A+ 
498,522 
 
  
Indiana, Series 2007, 5.500%, 3/01/37 
 
 
 
515 
  
Indiana Health Facility Financing Authority, Revenue Bonds, Community Foundation of Northwest 
3/17 at 100.00 
N/R (4) 
531,480 
 
  
Indiana, Series 2007, 5.500%, 3/01/37 (Pre-refunded 3/01/17) 
 
 
 
750 
  
Purdue University, Indiana, University Revenue Bonds, Student Facility System Series 2009A, 
1/19 at 100.00 
AAA 
830,370 
 
  
5.000%, 7/01/23 (Pre-refunded 1/01/19) 
 
 
 
2,020 
  
Total Indiana 
 
 
2,169,039 
 
  
Iowa – 2.5% 
 
 
 
1,540 
  
Iowa Finance Authority, Iowa, Midwestern Disaster Area Revenue Bonds, Iowa Fertilizer Company 
No Opt. Call 
B+ 
1,604,464 
 
  
Project, Series 2013, 5.000%, 12/01/19 
 
 
 
1,000 
  
Iowa Tobacco Settlement Authority, Asset Backed Settlement Revenue Bonds, Series 2005C, 
12/16 at 100.00 
B+ 
1,000,070 
 
  
5.375%, 6/01/38 
 
 
 
4,000 
  
Iowa Tobacco Settlement Authority, Tobacco Asset-Backed Revenue Bonds, Series 2005B, 
6/17 at 100.00 
B+ 
4,016,440 
 
  
5.600%, 6/01/34 
 
 
 
6,540 
  
Total Iowa 
 
 
6,620,974 
 
  
Kentucky – 1.1% 
 
 
 
2,500 
  
Kentucky Economic Development Finance Authority, Hospital Revenue Bonds, Baptist Healthcare 
8/21 at 100.00 
A+ 
2,794,875 
 
  
System Obligated Group, Series 2011, 5.250%, 8/15/46 
 
 
 
 
  
Massachusetts – 1.3% 
 
 
 
1,075 
  
Martha’s Vineyard Land Bank, Massachusetts, Revenue Bonds, Refunding Series 2006, 5.000%, 
5/17 at 100.00 
A– 
1,113,765 
 
  
5/01/18 – AMBAC Insured 
 
 
 
500 
  
Massachusetts Health and Educational Facilities Authority, Revenue Bonds, CareGroup Inc., 
7/18 at 100.00 
A– (4) 
543,155 
 
  
Series 2008E-1 &2, 5.000%, 7/01/28 (Pre-refunded 7/01/18) 
 
 
 
1,775 
  
Massachusetts Housing Finance Agency, Housing Bonds, Series 2009F, 5.700%, 6/01/40 
12/18 at 100.00 
AA– 
1,884,074 
 
  
(Alternative Minimum Tax) 
 
 
 
3,350 
  
Total Massachusetts 
 
 
3,540,994 
 
  
Michigan – 3.3% 
 
 
 
355 
  
Detroit Water and Sewerage Department, Michigan, Sewage Disposal System Revenue Bonds, 
7/22 at 100.00 
A– 
405,066 
 
  
Refunding Senior Lien Series 2012A, 5.250%, 7/01/39 
 
 
 
1,500 
  
Detroit, Michigan, Sewer Disposal System Revenue Bonds, Second Lien, Series 2001E, 5.750%, 
7/18 at 100.00 
AA+ 
1,626,240 
 
  
7/01/31 – BHAC Insured 
 
 
 
2,500 
  
Detroit, Michigan, Sewer Disposal System Revenue Bonds, Second Lien, Series 2006B, 5.000%, 
7/16 at 100.00 
AA– 
2,508,675 
 
  
7/01/33 – FGIC Insured 
 
 
 
2,075 
  
Detroit, Michigan, Water Supply System Senior Lien Revenue Bonds, Series 2004A, 4.500%, 
7/16 at 100.00 
AA– 
2,081,287 
 
  
7/01/25 – NPFG Insured 
 
 
 
2,000 
  
Portage Public Schools, Kalamazoo County, Michigan, General Obligation Bonds, School Building 
5/18 at 100.00 
AA (4) 
2,160,880 
 
  
& Site Series 2008, 5.000%, 5/01/21 (Pre-refunded 5/01/18) – AGM Insured 
 
 
 
8,430 
  
Total Michigan 
 
 
8,782,148 
 
  
Minnesota – 2.3% 
 
 
 
6,075 
  
Minnesota State, General Obligation Bonds, Various Purpose Series 2013A, 5.000%, 8/01/16 
No Opt. Call 
AA+ 
6,099,118 
 
  
Missouri – 2.7% 
 
 
 
360 
  
Bi-State Development Agency of the Missouri-Illinois Metropolitan District, Mass Transit Sales 
10/18 at 100.00 
AA+ 
392,753 
 
  
Tax Appropriation Bonds, Refunding Combined Lien Series 2013A, 5.000%, 10/01/28 
 
 
 
 
  
Kansas City Municipal Assistance Corporation, Missouri, Leasehold Revenue Bonds, 
 
 
 
 
  
Series 2004B-1: 
 
 
 
1,165 
  
0.000%, 4/15/23 – AMBAC Insured 
No Opt. Call 
AA 
1,031,945 
5,000 
  
0.000%, 4/15/30 – AMBAC Insured 
No Opt. Call 
AA– 
3,419,000 
2,000 
  
Missouri Health and Educational Facilities Authority, Health Facilities Revenue Bonds, 
11/23 at 100.00 
A2 
2,334,060 
 
  
CoxHealth, Series 2013A, 5.000%, 11/15/38 
 
 
 
8,525 
  
Total Missouri 
 
 
7,177,758 
 
  
Nevada – 1.7% 
 
 
 
750 
  
Clark County, Nevada, Airport Revenue Bonds, Tender Option Bond Trust Series 2016-XG0028, 
No Opt. Call 
A+ 
1,235,910 
 
  
19.046%, 1/01/18 (IF) 
 
 
 
1,250 
  
Clark County, Nevada, Passenger Facility Charge Revenue Bonds, Las Vegas-McCarran 
1/20 at 100.00 
A+ 
1,407,550 
 
  
International Airport, Series 2010A, 5.250%, 7/01/42 
 
 
 
1,500 
  
Las Vegas Redevelopment Agency, Nevada, Tax Increment Revenue Bonds, Series 2009A, 8.000%, 
6/19 at 100.00 
BBB+ (4) 
1,810,185 
 
  
6/15/30 (Pre-refunded 6/15/19) 
 
 
 
3,500 
  
Total Nevada 
 
 
4,453,645 
 
  
New Jersey – 9.5% 
 
 
 
940 
  
New Jersey Economic Development Authority, Private Activity Bonds, The Goethals Bridge 
1/24 at 100.00 
AA 
1,097,356 
 
  
Replacement Project, Series 2013, 5.125%, 1/01/39 – AGM Insured (Alternative Minimum Tax) 
 
 
 
2,550 
  
New Jersey Economic Development Authority, Revenue Bonds, Motor Vehicle Surcharge, Series 
1/17 at 100.00 
AA– 
2,576,903 
 
  
2004A, 5.250%, 7/01/33 – NPFG Insured 
 
 
 
1,035 
  
New Jersey Economic Development Authority, School Facilities Construction Financing Program 
3/21 at 100.00 
A– 
1,138,572 
 
  
Bonds, Refunding Series 2011GG, 5.000%, 9/01/22 
 
 
 
260 
  
New Jersey Health Care Facilities Financing Authority, Revenue Bonds, University Hospital 
7/25 at 100.00 
AA 
317,145 
 
  
Issue, Refunding Series 2015A, 5.000%, 7/01/29 – AGM Insured 
 
 
 
35,000 
  
New Jersey Transportation Trust Fund Authority, Transportation System Bonds, Refunding Series 
No Opt. Call 
AA 
17,677,450 
 
  
2006C, 0.000%, 12/15/34 – AGM Insured 
 
 
 
2,500 
  
Tobacco Settlement Financing Corporation, New Jersey, Tobacco Settlement Asset-Backed Bonds, 
6/17 at 100.00 
B– 
2,461,025 
 
  
Series 2007-1A, 5.000%, 6/01/41 
 
 
 
42,285 
  
Total New Jersey 
 
 
25,268,451 
 
  
New Mexico – 2.1% 
 
 
 
1,000 
  
New Mexico Mortgage Finance Authority, Multifamily Housing Revenue Bonds, St Anthony, Series 
9/17 at 100.00 
N/R 
1,017,930 
 
  
2007A, 5.250%, 9/01/42 (Alternative Minimum Tax) 
 
 
 
4,650 
  
State of New Mexico, State Severance Tax Revenue Bonds, Refunding Series 2010D, 5.000%, 7/01/16 
No Opt. Call 
Aa2 
4,650,605 
5,650 
  
Total New Mexico 
 
 
5,668,535 
 
  
New York – 4.0% 
 
 
 
4,500 
  
Dormitory Authority of the State of New York, State Personal Income Tax Revenue Bonds, 
9/16 at 100.00 
N/R (4) 
4,542,975 
 
  
Education Series 2006D, 5.000%, 3/15/36 (Pre-refunded 9/15/16) 
 
 
 
500 
  
Hudson Yards Infrastructure Corporation, New York, Revenue Bonds, Senior Fiscal 2012 Series 
2/21 at 100.00 
A 
576,785 
 
  
2011A, 5.250%, 2/15/47 
 
 
 
1,810 
  
Hudson Yards Infrastructure Corporation, New York, Revenue Bonds, Series 2006A, 5.000%, 
2/17 at 100.00 
A 
1,855,992 
 
  
2/15/47 – FGIC Insured 
 
 
 
840 
  
New York City Transitional Finance Authority, New York, Future Tax Secured Bonds, Fiscal 
5/17 at 100.00 
AAA 
867,997 
 
  
Series 2007B, 4.750%, 11/01/27 
 
 
 
1,660 
  
New York City Transitional Finance Authority, New York, Future Tax Secured Bonds, Fiscal 
5/17 at 100.00 
N/R (4) 
1,717,336 
 
  
Series 2007B, 4.750%, 11/01/27 (Pre-refunded 5/01/17) 
 
 
 
780 
  
Port Authority of New York and New Jersey, Special Project Bonds, JFK International Air 
12/20 at 100.00 
Baa1 
922,935 
 
  
Terminal LLC Project, Eighth Series 2010, 6.000%, 12/01/42 
 
 
 
10,090 
  
Total New York 
 
 
10,484,020 
 
  
North Carolina – 1.4% 
 
 
 
1,000 
  
North Carolina Eastern Municipal Power Agency, Power System Revenue Bonds, Series 2008C, 
1/19 at 100.00 
AAA 
1,149,700 
 
  
6.750%, 1/01/24 (Pre-refunded 1/01/19) 
 
 
 
2,440 
  
Union County, North Carolina, General Obligation Bonds, Series 2007D, 5.000%, 3/01/21 
3/17 at 100.00 
Aaa 
2,512,810 
 
  
(Pre-refunded 3/01/17) – NPFG Insured 
 
 
 
3,440 
  
Total North Carolina 
 
 
3,662,510 
 
  
Ohio – 2.3% 
 
 
 
 
  
Buckeye Tobacco Settlement Financing Authority, Ohio, Tobacco Settlement Asset-Backed Revenue 
 
 
 
 
  
Bonds, Senior Lien, Series 2007A-2: 
 
 
 
1,670 
  
6.000%, 6/01/42 
6/17 at 100.00 
B– 
1,671,236 
1,000 
  
6.500%, 6/01/47 
6/17 at 100.00 
B– 
1,026,170 
1,975 
  
Buckeye Tobacco Settlement Financing Authority, Ohio, Tobacco Settlement Asset-Backed Revenue 
6/22 at 100.00 
B– 
2,017,877 
 
  
Bonds, Senior Lien, Series 2007A-3, 6.250%, 6/01/37 
 
 
 
1,105 
  
Ohio Turnpike Commission, Turnpike Revenue Bonds, Infrastructure Project, Junior Lien Series 
2/23 at 100.00 
A+ 
1,291,215 
 
  
2013A-1, 5.000%, 2/15/48 
 
 
 
5,750 
  
Total Ohio 
 
 
6,006,498 
 
  
Oklahoma – 1.1% 
 
 
 
1,000 
  
Norman Regional Hospital Authority, Oklahoma, Hospital Revenue Bonds, Series 2005, 
9/16 at 100.00 
BBB 
1,004,940 
 
  
5.375%, 9/01/36 
 
 
 
2,000 
  
Oklahoma City, Oklahoma, General Obligation Bonds, Refunding Series 2015, 2.000%, 9/01/16 
No Opt. Call 
AAA 
2,005,440 
3,000 
  
Total Oklahoma 
 
 
3,010,380 
 
  
Pennsylvania – 0.6% 
 
 
 
1,490 
  
Pennsylvania Turnpike Commission, Motor License Fund-Enhanced Subordinate Special Revenue 
12/20 at 100.00 
AA– 
1,692,282 
 
  
Bonds, Series 2010B, 5.000%, 12/01/30 
 
 
 
 
  
Puerto Rico – 1.6% 
 
 
 
 
  
Puerto Rico Sales Tax Financing Corporation, Sales Tax Revenue Bonds, Series 2007A: 
 
 
 
17,500 
  
0.000%, 8/01/41 – NPFG Insured 
No Opt. Call 
AA– 
3,946,600 
1,000 
  
0.000%, 8/01/43 – NPFG Insured 
No Opt. Call 
AA– 
200,320 
18,500 
  
Total Puerto Rico 
 
 
4,146,920 
 
  
Texas – 10.6% 
 
 
 
250 
  
Central Texas Regional Mobility Authority, Revenue Bonds, Senior Lien Series 2011, 6.000%, 
1/21 at 100.00 
BBB+ (4) 
305,458 
 
  
1/01/41 (Pre-refunded 1/01/21) 
 
 
 
110 
  
Central Texas Regional Mobility Authority, Revenue Bonds, Senior Lien, Series 2015A, 
7/25 at 100.00 
BBB+ 
133,728 
 
  
5.000%, 1/01/33 
 
 
 
3,000 
  
Fort Worth Independent School District, Tarrant County, Texas, General Obligation Bonds, 
No Opt. Call 
AAA 
3,018,150 
 
  
Refunding Series 2006, 5.000%, 2/15/18 (6) 
 
 
 
5,565 
  
Grand Parkway Transportation Corporation, Texas, System Toll Revenue Bonds, First Tier Series 
10/23 at 100.00 
BBB+ 
6,532,809 
 
  
2013A, 5.500%, 4/01/53 
 
 
 
3,415 
  
Harris County-Houston Sports Authority, Texas, Revenue Bonds, Junior Lien Series 2001H, 
No Opt. Call 
AA– 
2,112,314 
 
  
0.000%, 11/15/30 – NPFG Insured 
 
 
 
4,230 
  
Harris County-Houston Sports Authority, Texas, Revenue Bonds, Third Lien Series 2004A-3, 
11/24 at 52.47 
AA– 
1,643,397 
 
  
0.000%, 11/15/35 – NPFG Insured 
 
 
 
4,015 
  
Harris County-Houston Sports Authority, Texas, Special Revenue Bonds, Refunding Senior Lien 
11/30 at 61.17 
AA 
1,664,258 
 
  
Series 2001A, 0.000%, 11/15/38 – NPFG Insured 
 
 
 
1,780 
  
Leander Independent School District, Williamson and Travis Counties, Texas, General Obligation 
8/16 at 35.23 
AAA 
626,649 
 
  
Bonds, Series 2007, 0.000%, 8/15/37 (Pre-refunded 8/15/16) 
 
 
 
2,260 
  
Love Field Airport Modernization Corporation, Texas, Special Facilities Revenue Bonds, 
11/20 at 100.00 
Baa1 
2,586,525 
 
  
Southwest Airlines Company, Series 2010, 5.250%, 11/01/40 
 
 
 
2,000 
  
North Texas Tollway Authority, System Revenue Bonds, Refunding First Tier Capital Appreciation 
1/25 at 100.00 
A1 
2,672,780 
 
  
Series 2008I, 6.500%, 1/01/43 
 
 
 
5,000 
  
Texas Municipal Gas Acquisition and Supply Corporation III, Gas Supply Revenue Bonds, Series 
No Opt. Call 
A3 
5,891,250 
 
  
2012, 5.000%, 12/15/26 
 
 
 
830 
  
Wood County Central Hospital District, Texas, Revenue Bonds, East Texas Medical Center Quitman 
11/21 at 100.00 
Baa3 
966,801 
 
  
Project, Series 2011, 6.000%, 11/01/41 
 
 
 
32,455 
  
Total Texas 
 
 
28,154,119 
 
  
Virginia – 4.0% 
 
 
 
1,000 
  
Fairfax County Economic Development Authority, Virginia, Residential Care Facilities Mortgage 
10/17 at 100.00 
BBB 
1,038,120 
 
  
Revenue Bonds, Goodwin House, Inc., Series 2007A, 5.125%, 10/01/42 
 
 
 
2,000 
  
Metropolitan Washington Airports Authority, Virginia, Dulles Toll Road Revenue Bonds, Dulles 
10/28 at 100.00 
BBB+ 
2,435,160 
 
  
Metrorail Capital Appreciation, Second Senior Lien Series 2010B, 0.000%, 10/01/44 (5) 
 
 
 
1,500 
  
Virginia Public Building Authority, Public Facilities Revenue Bonds, Series 2009B, 
No Opt. Call 
AA+ 
1,572,645 
 
  
5.000%, 8/01/17 
 
 
 
 
  
Virginia Small Business Financing Authority, Senior Lien Revenue Bonds, Elizabeth River 
 
 
 
 
  
Crossing, Opco LLC Project, Series 2012: 
 
 
 
1,000 
  
5.250%, 1/01/32 (Alternative Minimum Tax) 
7/22 at 100.00 
BBB 
1,154,210 
1,470 
  
6.000%, 1/01/37 (Alternative Minimum Tax) 
7/22 at 100.00 
BBB 
1,766,940 
1,010 
  
5.500%, 1/01/42 (Alternative Minimum Tax) 
7/22 at 100.00 
BBB 
1,176,084 
1,390 
  
Virginia Small Business Financing Authority, Wellmont Health System Project Revenue Bonds, 
9/17 at 100.00 
BBB+ 
1,445,127 
 
  
Series 2007A, 5.250%, 9/01/37 
 
 
 
9,370 
  
Total Virginia 
 
 
10,588,286 
 
  
Washington – 2.9% 
 
 
 
2,250 
  
Seattle, Washington, General Obligation Bonds, Refunding and Improvement Series 2010B, 
No Opt. Call 
AAA 
2,258,955 
 
  
5.000%, 8/01/16 (6) 
 
 
 
990 
  
Washington Health Care Facilities Authority, Revenue Bonds, Fred Hutchinson Cancer Research 
1/21 at 100.00 
A 
1,131,639 
 
  
Center, Series 2011A, 5.625%, 1/01/35 
 
 
 
2,500 
  
Washington State, General Obligation Motor Vehicle Fuel Tax Bonds, Series 2008D, 5.000%, 
1/18 at 100.00 
AA+ (4) 
2,663,725 
 
  
1/01/33 (Pre-refunded 1/01/18) 
 
 
 
2,115 
  
Washington State, Motor Vehicle Fuel Tax General Obligation Bonds, Series 2003F, 0.000%, 
No Opt. Call 
AA+ 
1,694,136 
 
  
12/01/27 – NPFG Insured 
 
 
 
7,855 
  
Total Washington 
 
 
7,748,455 
 
  
West Virginia – 0.7% 
 
 
 
1,500 
  
West Virginia Hospital Finance Authority, Hospital Revenue Bonds, West Virginia United Health 
6/23 at 100.00 
A 
1,801,680 
 
  
System Obligated Group, Refunding & Improvement Series 2013A, 5.500%, 6/01/44 
 
 
 
 
  
Wisconsin – 1.6% 
 
 
 
1,645 
  
Wisconsin Health and Educational Facilities Authority, Revenue Bonds, Mercy Alliance, Inc., 
6/22 at 100.00 
A3 
1,874,313 
 
  
Series 2012, 5.000%, 6/01/39 
 
 
 
1,500 
  
Wisconsin Health and Educational Facilities Authority, Revenue Bonds, Wheaton Franciscan 
8/16 at 100.00 
N/R (4) 
1,508,715 
 
  
Healthcare System, Series 2006A, 5.250%, 8/15/31 (Pre-refunded 8/15/16) 
 
 
 
775 
  
Wisconsin, General Obligation Refunding Bonds, Series 2003-3, 5.000%, 11/01/26 
11/16 at 100.00 
AA 
778,116 
3,920 
  
Total Wisconsin 
 
 
4,161,144 
$ 334,475 
  
Total Municipal Bonds (cost $230,154,079) 
 
 
269,981,663 
             
Principal 
  
 
 
 
 
 
Amount (000) 
  
Description (1) 
Coupon 
Maturity 
Ratings (3) 
Value 
 
  
CORPORATE BONDS – 0.0% 
 
 
 
 
             
 
  
Transportation – 0.0% 
 
 
 
 
$ 210 
  
Las Vegas Monorail Company, Senior Interest Bonds (7), (8) 
5.500% 
7/15/19 
N/R 
$ 6,297 
56 
  
Las Vegas Monorail Company, Senior Interest Bonds (7), (8) 
5.500% 
7/15/55 
N/R 
1,675 
$ 266 
  
Total Corporate Bonds (cost $23,822) 
 
 
 
7,972 
 
  
Total Long-Term Investments (cost $230,177,901) 
 
 
 
269,989,635 
 
  
Other Assets Less Liabilities – (1.9)% (9) 
 
 
 
(5,129,645) 
 
  
Net Assets – 100% 
 
 
 
$ 264,859,990 
 

Investments in Derivatives as of June 30, 2016 
 
 
 
 
 
Interest Rate Swaps 
 
 
 
 
 
 
 
 
 
 
Fund 
 
 
Fixed Rate 
 
 
Unrealized 
 
Notional 
Pay/Receive 
Floating Rate 
Fixed Rate 
Payment 
Effective 
Termination 
Appreciation 
Counterparty 
Amount 
Floating Rate 
Index 
(Annualized) 
Frequency 
Date (10) 
Date 
(Depreciation) 
JPMorgan Chase Bank, N.A. 
$7,000,000 
Receive 
USD-BMA 
1.190% 
Quarterly 
7/31/17 
7/31/27 
$18,066 
 
Fair Value Measurements
Fair value is defined as the price that would be received upon selling an investment or transferring a liability in an orderly transaction to an independent buyer in the principal or most advantageous market for the investment. A three-tier hierarchy is used to maximize the use of observable market data and minimize the use of unobservable inputs and to establish classification of fair value measurements for disclosure purposes. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability. Observable inputs are based on market data obtained from sources independent of the reporting entity. Unobservable inputs reflect the reporting entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability. Unobservable inputs are based on the best information available in the circumstances. The following is a summary of the three-tiered hierarchy of valuation input levels.
Level 1 – Inputs are unadjusted and prices are determined using quoted prices in active markets for identical securities.
Level 2 – Prices are determined using other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.).
Level 3 – Prices are determined using significant unobservable inputs (including management’s assumptions in determining the fair value of investments).
The inputs or methodologies used for valuing securities are not an indication of the risk associated with investing in those securities. The following is a summary of the Fund's fair value measurements as of the end of the reporting period:
 
Level 1 
Level 2 
Level 3 
Total 
Long-Term Investments: 
 
 
 
 
Municipal Bonds 
$ — 
$269,981,663 
$     — 
$269,981,663 
Corporate Bonds 
— 
— 
7,972 
7,972 
Investments in Derivatives: 
 
 
 
 
Interest Rate Swaps* 
— 
18,066 
— 
18,066 
Total 
$ — 
$269,999,729 
$ 7,972 
$270,007,701 
* Represents net unrealized appreciation (depreciation).
Income Tax Information
The following information is presented on an income tax basis. Differences between amounts for financial statement and federal income tax purposes are primarily due to timing differences in recognizing taxable market discount, timing differences in recognizing certain gains and losses on investment transactions and the treatment of investments in inverse floating rate securities reflected as financing transactions, if any. To the extent that differences arise that are permanent in nature, such amounts are reclassified within the capital accounts on the Statement of Assets and Liabilities presented in the annual report, based on their federal tax basis treatment; temporary differences do not require reclassification. Temporary and permanent differences do not impact the net asset value of the Fund.
As of June 30, 2016, the cost of investments (excluding investments in derivatives) was $228,449,891.
Gross unrealized appreciation and gross unrealized depreciation of investments (excluding investments in derivatives) as of June 30, 2016, were as follows:
   
Gross unrealized: 
 
Appreciation 
$41,619,212 
Depreciation 
(79,468) 
Net unrealized appreciation (depreciation) of investments 
$41,539,744 
 
(1) 
  
All percentages shown in the Portfolio of Investments are based on net assets. 
(2) 
  
Optional Call Provisions: Dates (month and year) and prices of the earliest optional call or redemption. 
 
  
There may be other call provisions at varying prices at later dates. Certain mortgage-backed securities 
 
  
may be subject to periodic principal paydowns. 
(3) 
  
For financial reporting purposes, the ratings disclosed are the highest of Standard & Poor’s Group 
 
  
("Standard & Poor's"), Moody’s Investors Service, Inc. ("Moody's") or Fitch, Inc. ("Fitch") rating. Ratings below 
 
  
BBB by Standard & Poor’s, Baa by Moody’s or BBB by Fitch are considered to be below investment grade. 
 
  
Holdings designated N/R are not rated by any of these national rating agencies. 
(4) 
  
Backed by an escrow or trust containing sufficient U.S. Government or U.S. Government agency securities, 
 
  
which ensure the timely payment of principal and interest. Certain bonds backed by U.S. Government or 
agency securities are regarded as having an implied rating equal to the rating of such securities.
(5) 
  
Step-up coupon. The rate shown is the coupon as of the end of the reporting period. 
(6) 
  
Investment, or portion of investment, has been pledged to collateralize the net payment obligations for 
 
  
investments in derivatives and/or inverse floating rate transactions. 
(7) 
  
Investment valued at fair value using methods determined in good faith by, or at the discretion of, the 
 
  
Board. For fair value measurement disclosure purposes, investment classified as Level 3. 
(8) 
  
During January 2010, Las Vegas Monorail Company (“Las Vegas Monorail”) filed for federal bankruptcy 
 
  
protection. During March 2012, Las Vegas Monorail emerged from federal bankruptcy with the acceptance 
 
  
of a reorganization plan assigned by the Federal Bankruptcy Court. Under the reorganization plan, the Fund 
 
  
surrendered its Las Vegas Monorail Project Revenue Bonds, First Tier, Series 2000 and in turn received two 
 
  
senior interest corporate bonds: the first with an annual coupon rate of 5.500% maturing on July 15, 2019 
 
  
and the second with an annual coupon rate of 3.000% (5.500% after December 31, 2015) maturing on 
 
  
July 15, 2055. The Fund is not accruing income for either senior interest corporate bond. 
(9) 
  
Other assets less liabilities includes the unrealized appreciation (depreciation) of certain over-the-counter 
("OTC") derivatives as well as the OTC-cleared and exchange-traded derivatives, when applicable.
(10) 
  
Effective date represents the date on which both the Fund and Counterparty commence interest payment 
 
  
accruals on each contract. 
(WI/DD) 
  
Investment, or portion of investment, purchased on a when-issued or delayed delivery basis. 
(ETM) 
  
Escrowed to maturity. 
(IF) 
  
Inverse floating rate investment. 
USD-BMA 
  
United States Dollar-Bond Market Association 
 
 
Item 2. Controls and Procedures.

a.  
The registrant's principal executive and principal financial officers, or persons performing similar functions, have concluded that the registrant's disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the "1940 Act") (17 CFR 270.30a-3(c))) are effective, as of a date within 90 days of the filing date of this report that includes the disclosure required by this paragraph, based on their evaluation of the controls and procedures required by Rule 30a-3(b) under the 1940 Act (17 CFR 270.30a-3(b)) and Rule 13a-15(b) or 15d-15(b) under the Securities Exchange Act of 1934 (17 CFR 240.13a-15(b) or 240.15d-15(b)).
 
b.  
There were no changes in the registrant's internal control over financial reporting (as defined in Rule 30a-3(d) under the 1940 Act (17 CFR 270.30a-3(d)) that occurred during the registrant's last fiscal quarter that have materially affected, or are reasonably likely to materially affect, the registrant's internal control over financial reporting.
 
Item 3. Exhibits.

File as exhibits as part of this Form a separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the 1940 Act (17 CFR 270.30a-2(a)), exactly as set forth below: See EX-99 CERT attached hereto.

 
 
SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.
 
(Registrant)  Nuveen Select Tax-Free Income Portfolio 
 
By (Signature and Title) /s/ Kevin J. McCarthy                    
       Kevin J. McCarthy
     Vice President and Secretary
                                         
Date:         August 29, 2016        
 
Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.
 
By (Signature and Title) /s/ Gifford R. Zimmerman            
       Gifford R. Zimmerman
     Chief Administrative Officer (principal executive officer)
                        
Date:         August 29, 2016        
 
By (Signature and Title) /s/ Stephen D. Foy                         
 
     Stephen D. Foy
     Vice President and Controller (principal financial officer)
                                                                                         
Date:         August 29, 2016