Financial giant Lehman Brothers filed for bankruptcy protection Monday, but experts say the biggest bankruptcy case in U.S. history won?t likely impact those whose retirement funds are wrapped up in the company.

"If you own stock in Lehman Brothers, you're toast,? says Dowling College economist Dr. Irwin Kellner. However, 401(k) holders will be safe because of the Securities Investor Protection Corporation, which covers Lehman?s retail security customers.

Lehman Brothers fell under the weight of $60 billion in soured real estate holdings. The bankruptcy announcement now leaves the jobs about 25,000 employees uncertain.

The news about Lehman Brothers as well as Bank of America?s intention to buy Merrill Lynch sent the Dow Jones Industrial Average down 500 points Monday.

New York Gov. David Paterson reacted saying, "The ramifications of the plight of many of these companies will probably not be fully appreciated for months, maybe even years."

Paterson announced he will step in to help New York-based insurance company AIG by allowing it to borrow $20 billion from its subsidiaries. The company has recently seen its stock plummet 45 percent.

AP wire reports contributed to this article