Everyone has his limits, and private equity firms appear to be reaching theirs. For the fourth time in 10 days, private equity firms backed away from a deal judged too expensive, in this case, the $3.8 billion price tag for Jones Apparel. “There has to be a point at which you just can’t pay any more, otherwise the returns will be so low that you will struggle to raise future investment funds,” Tom Lamb of Barclays Private Equity said in a Times of London interview, commenting on the news. It’s not as if the p.e firms haven’t had a little help in making their decisions. Lamb says, in many instances, the banks that lend to the p.e. funds are crying enough is enough, as they find themselves putting up cash for ever-higher percentages of the transaction. Pete Peterson, co-founder of The Blackstone Group, told the Times that in this environment, for private equity firms to succeed, they will have to “concentrate much more on improving the operating performance of their portfolio companies than relying on financial engineering and market valuations.”