Only on Wall Street, in the rarefied realm of buyout moguls, could you actually have too much money. Private-equity houses, where corporate takeovers are planned and plotted, sit atop an estimated $500 billion. But the deal makers are desperate to find deals worth doing, and the clock is ticking. The stores of money inside the private-equity industry have ramifications far beyond the bid 'em up crowd on Wall Street. Millions of Americans -- investors, employees, retirees -- have a stake in the game too. Corporate buyout specialists generally raise money from big investors and then buy undervalued or under-appreciated companies. To maximize investment returns, they typically leverage their cash with loans from banks or bond investors. Given the prices being paid for companies, investors' returns over the life of the fund are likely to drop into the low to mid-teens, said Hugh H. MacArthur, head of global private equity at Bain & Company, a consulting firm that used to be affiliated with Bain Capital, the private equity firm. Returns will be even lower once fees are factored in. Private equity firms typically charge an annual fee of 2 percent and take a 20 percent cut of any profits. While investing in private equity will probably be more lucrative than investing in public markets, 'those are far from the gross returns of the mid- to high teens that we saw a few years ago,' MacArthur said. One factor in the modest forecast is rising prices for buyouts. Kelly DePonte, a partner at Probitas Partners in San Francisco, which helps private-equity firms raise money, said 'tough competition for deals' had driven up valuations recently. Last year, when banks balked at financing deals and private-equity firms worried the economic crisis would drag on, the number of deals -- and prices paid -- fell sharply. These days, even small and midsize companies are in a bidding frenzy. More than a dozen buyout firms made initial bids for the Virtual Radiologic Corporation, a firm that interprets medical images remotely. Providence Equity Partners eventually paid a 41 percent premium for the company. When a small online education company called Plato Learning hung up a 'for sale' sign, several suitors showed interest. When Plato last tried to sell itself, in the fall of 2007, it found no takers. Private-equity players concede that competition has heated up and prices are rising. They argue that prices, from a historical standpoint, remain attractive. Prices are well below the stratospheric levels of 2007 and 2008, according to Capital IQ. Buyout executives also say it is too soon to determine what profits will come from these deals. Plus, they say, losers in bidding wars always claim the winners overpaid. 