NEW YORK - JPMorgan Chase & Co.’s biggest challenge in integrating Bear Stearns Cos may be making sure there’s still something left to integrate.

An exodus of Bear employees, who could take their unsettled clients with them, may further erode what value is left at the fallen investment bank.

"The people who make money for Bear Stearns get in the elevator and leave every night," said David Hinkel, who advises companies on merger integration issues for consulting firm Towers Perrin. "Due to the nature of the business, the people are the business."

Wesley Fredericks, a partner at law firm Heller Ehrman said, "What often happens in these situations is that the cream of the crop goes early and can re-establish themselves somewhere else."

Motivating and keeping Bear’s 14,000 employees, which collectively lost about $3 billion on their Bear holdings over the past month, as the investment bank collapsed, is a big problem for JPMorgan. CEO Jamie Dimon has reportedly called rival Wall Street firms and warned them to back off.

On Monday, JPMorgan raised its offer for Bear, which last year traded above $170 a share, to about $10 a share in stock. The original bid on March 16 was about $2 a share. JPMorgan also struck a deal to buy 95 million new Bear shares, a stake of 39.5 percent.

All told, the deal will cost JPMorgan roughly $9 billion in stock, transaction-related costs, and potential losses from Bear’s portfolio.

The revised offer was intended to seal the deal and encourage Bear clients and employees to stay put. But employees are facing massive layoffs, with media reports saying up to half of Bear’s staff could get cut.

While doubts about the future of Bear businesses at JPMorgan persist, the bank has decided to integrate Bear’s prime brokerage and clearing operations. It is also keen on keeping the retail brokerage business, which will continue to operate under the Bear name, according to people familiar with JPMorgan’s plans.

"Uncertainty breeds fear. People are going to start to vote with their feet," said Towers Perrin’s Hinkel.

"You’ll have an initial wave of talent that will walk out of the organization immediately. The bigger concern is the second wave of people who will potentially leave six months from now. The longer this goes on, the greater the risk of talent flight will be."

In a bid to retain Bear employees, JPMorgan is offering packages to keep them from leaving.

Most bankers who are offered jobs by JPMorgan would receive a bonus in JPMorgan stock that matches their last bonus at Bear. Employees who are not offered jobs will receive a cash bonus of at least 30 percent of their 2007 compensation if they stay through the completion of the deal, according to people familiar with the situation.