We recently analyzed the PowerShares Buyback Achievers ETF (NYSEArca: PKW) and the Guggenheim Spin-Off ETF (NYSEArca: CSD) as part of an ongoing effort to unearth broad market ETFs that offer unique portfolios. What is compelling about CSD and PKW is that both focus on easy-to-understand though narrow concepts, buybacks and spin-offs.

Even more compelling are the returns offered by these two funds. In the past 12 months, the S&P 500 is up about 21%. CSD has offered better than double those returns and PKW has not been a slouch, either, gaining over 28%. [Spin-Off ETF Spinning Solid Returns]

Another niche play to consider is the First Trust US IPO Index Fund (NYSEArca: FPX). FPX celebrated its seventh birthday in April, but it is investors that have been fortunate enough to own FPX that should be doing celebrating. Yes, long gone are the 1990s when it seemed like every IPO was a big deal, but that has not mattered to FPX. FPX has even been able to shake-off Facebook’s (NasdaqGM: FB) post-IPO struggles. [IPO ETF Beats S&P 500 Despite Facebook Flop]

Besides being a niche play with an easily explained concept, FPX shares something in common with CSD and PKW: A track record of topping the broader market. Over the past five years, two years, 12 months and year-to-date, FPX has easily topped the S&P 500.

Investors should note how FPX does business because in the case of this ETF, IPO does not necessarily mean brand new stocks. Said another way, a hot IPO set to debut on June 30 could trade for months before being included in FPX’s index.

FPX is home to 100 stocks, none of which can exceed a weight of 10%. Interestingly, the ETF is also home to an array of familiar names as a fair amount of its holdings are either spin-offs, companies that were formerly public and then acquired only to go public again, or in the case of General Motors (NYSE: GM), a company that has come back from bankruptcy. Of FPX’s top-seven holdings, only Facebook is a true IPO. Five are spinoffs and then there is General Motors, the fund’s second-largest holding.