In almost every way, J.P. Morgan Chase & Co.'s agreement to buy Bear Stearns Cos. is no ordinary deal. Besides the remarkable speed and fire-sale price at which an agreement was reached, the acquisition spawned no small amount of legal and regulatory innovation on the fly.

When J.P. Morgan and Bear Stearns announced the deal on Sunday, they had already obtained "all necessary approvals" from federal regulators. It was no surprise to have the blessing of the Federal Reserve, which had agreed to help finance the transaction. But these approvals included "all other federal agencies"—meaning that antitrust regulators signed off on the bailout before the ink on the deal was dry.

At the same time, the merger agreement gives J.P. Morgan an option to buy Bear Stearns' new headquarters in Manhattan at the discounted price of $1.1 billion if the deal does not go through. The option for the real estate, on its face, is worth more than the $236 million price to buy all of Bear Stearns at $2 a share.

"Everything about this deal is unprecedented," said a person with knowledge of the negotiations. And, in fact, many aspects of it are "on the edge of the applicable law."

J.P. Morgan tacitly acknowledged as much when it estimated that its "transactional" costs, should the deal get shareholder approval, would total about $6 billion—a figure that includes considerable reserves for the anticipated cost of litigation over the collapse and sale of Bear Stearns.

Securities class-action lawsuits have been almost inevitable as Bear Stearns' enthusiasm for mortgage-backed securities relentlessly eroded the value of its stock. Compounding that loss were steadfast assurances by Bear Stearns executives that all was well with the firm, some as recently as last Thursday.

The first suits have already been filed. Coughlin Stoia Geller Rudman & Robbins filed a class action Monday in Manhattan federal court on behalf of Bear Stearns shareholders. Expect more.

"There's no question, given the representations made by Bear Stearns, that institutional investors will initiate securities-fraud lawsuits," said Blair Nicholas of Bernstein Litowitz Berger & Grossman. "You have a company that has wiped out 90 percent of its equity in less than a year and a half and less than a week ago said everything was okay.

"We are looking very, very seriously at this on behalf of our large institutional investor client base," Nicholas added.