In May, Invesco PowerShares announced the closing of 19 different exchange-traded funds. One of those was a fund investing strictly in foreign private-equity players, apparently due to low asset levels.

Now, PowerShares is proposing changes to its existing private-equity ETF. It has filed a request with the Securities and Exchange Commission for approval to what appears to be a conversion of the U.S.-focused PowerShares Listed Private Equity ETF (NYSE Arca: PSP) into a global portfolio.

In 2006, PSP came out as the first ETF of its kind. At the time, the market for public private-equity firms was somewhat limited, causing some investors to grouse that PSP had to stretch its portfolio a bit and include companies that shouldn't be considered pure private equity plays.

But in late 2007, the PowerShares International Listed Private Equity Portfolio (NYSE Arca: PFP) was launched. It came out just as credit markets were tanking and valuations of once-booming private equity firms began tumbling.

By the time PowerShares decided to pull the plug earlier this year, PFP had just $12.6 million in assets. (See related story here.)

Presumably, a switch to a more global portfolio would combine the top names in the existing holdings of PSP and the former PFP using a modified market-cap size weighting methodology.

No details of a new index were given in the filing, however. It might be worth noting that PSP currently charges an expense ratio of 0.60%.

After the changes, PSP will include some 40-60 different companies involved in lending or investing in privately held companies throughout the world.

PSP is certainly having a banner year after suffering a huge fall in 2008. The domestic-minded ETF lost more than 64% last year, but has gained 22%-plus so far in 2009.

You can read the filing here.