Throughout September, a monster rally for stock assets captured most of the headlines. Nevertheless, commodities, corporate bonds, high-yield bonds, foreign currencies -- heck, most real estate investment trusts -- are all logging 52-week highs.

The "all-assets-are-climbing" phenomenon goes hand-in-hand with the Fed's implied use of additional quantitative easing. Simply stated, the Fed's planned monetary stimulus to buy U.S. treasuries and/or mortgage-backed securities yet again, even while interest rates are already at an effective rate of 0%, further devalues the U.S. dollar; not surprisingly, the ultrastimulative monetary policy entices investors to buy anything other than the U.S. dollar -- from the least risky to the most risky.

It follows that it may not make all that much sense to talk about industry ETFs that are flying under the radar. After all, if everything goes up, why bother trying to set your portfolio apart?

Well, the simple answer is an effort at minimizing duplication and excessive risk. In other words, just because Thailand ( THD), Turkey ( TUR), and Indonesia ( IDX) are raking in the bucks, you probably shouldn't hold every single-country emerging-market ETF; these investments are highly correlated, and they are further out on the risk spectrum than many may realize.

So here are three subsector ETFs very few people have mentioned lately:

PowerShares Global Listed Private Equity ( PSP) This ETF was one of the worst casualties of the financial collapse. Its ties to the crisis didn't exactly help. Still, the business of "buying out" public corporations or acquiring distressed assets or lending capital has had a renaissance of sorts.

This is an exchange-traded investment that has risen 170% off of its March 9, 2009, lows. Yet unlike other casualties of finance, such as the KBW Bank Index ( KBE), an investment that has been in a downtrend since April. PowerShares Global Listed Private Equity ( PSP) is experiencing a technical uptrend since most U.S. stock assets bottomed in early July. PSP also boasts a SEC 30-day yield in the area of 3%. (Year-over-year, PSP is up about 5%, whereas KBE is down about 4%.)

If you liked this article you might like

KKR Hitches a Ride With Lyft in $600M Series G Round

PepsiCo to Report Earnings Before Opening Bell Thursday

PSP Makes Bullish Cross Above Critical Moving Average

Global Private Equity ETFs Live and Die by the Sword

Using an ETF Portfolio to Mimic an Endowment Portfolio