Rob Arnott’s footprint on the ETF industry just might be getting a little bit bigger. ProShares, the Maryland-based leveraged and inverse ETF giant, recently filed details with the SEC on an ETF that would seek to track the performance of the RAFI US Equity Long/Short Index. That benchmark is based on a methodology devised by Arnott’s firm, Research Affiliates, that more and more investors are embracing as an alternative to traditional market cap weighting. PowerShares currently offers a handful of equity ETFs linked to RAFI indexes, and earlier this year swapped out the index on its high yield bond ETF (PHB) in favor of a RAFI index. Steering clear of market capitalization, the RAFI methodology uses four “fundamental” metrics to determine a company’s size: sales, cash flow, dividends, and book value [see Do You Need A RAFI ETF?]. Determining the holdings of the index underlying the proposed long/short ETF would [...] Click here to read the original article on ETFdb.com. Related Stories: ProShares Planning Short, Leveraged Regional Bank ETFs IndexIQ Planning 130/30 ETF Direxion Planning 130/30 ETF