Some would say it’s the dirty “secret” of private equity. While leveraged buyout firms often do well to turn companies around, it’s the fees from deals that line their pockets, not the profits from the sale of the business. Now, a new study by two professors at Penn’s Wharton School lifts the lid on this “secret.”

In a 53 page study dated Sept. 9 and featured in the Wall Street Journal on Thursday, the findings of professors Andrew Metrick and Ayako Yasuda hardly help private equity firms with their argument that the pending carried interest bill will damage the buyout industry.

According to the Journal, the study shows that, “on average, leveraged-buyout funds can expect to collect $10.35 in management fees for every $100 they manage. In comparison, slightly more than half as much — $5.41 for every $100 — comes from carried interest.”

That seems to support the argument from other academics and even pension fund managers who say that the carried interest bill is unlikely to hurt private equity returns, and as a result, probably won’t impact the pension funds all that much. Such sentiments were present during last week’s testimonies on Capital Hill.

President Bush is likely to veto a tax increase, but the tide has turned a bit against the private equity industry’s resistance toward the carried interest issue. After all, if you’re Steve Schwarzman and you’re worth $7 billion, what’s a jacked up rate on profits really going to do your personal fortune?