“They tried to make these guys the poster children for the recession,” said Thomas E. Peisch, a partner at the law firm of Conn Kavanaugh Rosenthal Peisch & Ford in Boston, who was not connected with the case. “The lesson is that the government has to be pretty careful in the future about the cases it selects to prosecute because they obviously didn’t even come close to selling it here.”

Image Matthew M. Tannin, a former hedge fund chief at Bear Stearns, leaving court on Tuesday after his acquittal. The verdict was the first in a major criminal case stemming from the financial crisis. Credit... Shannon Stapleton/Reuters

In a statement, the United States attorney’s office for the Eastern District of New York expressed disappointment with the outcome. “But the jurors have spoken,” the statement said, “and we accept their verdict. Honesty and integrity are the principles upon which our financial markets function. Enforcing and protecting those principles will continue to be one of the principal efforts of this office.”

Mr. Cioffi was also found not guilty of insider trading charges on accusations that he moved $2 million he had invested in one of the failing funds to another less risky fund while telling investors he was adding to his position.

The verdict is expected to have wide-ranging implications for how the government approaches similar white-collar cases.

It has been closely watched by law enforcement and other prosecutors, especially in light of the recent contentions of insider trading centered around the billionaire Raj Rajaratnam.

“These acquittals provide a cautionary tale for white-collar investigations premised on facially ‘smoking gun’ e-mails,” said John Hueston, who prosecuted Enron’s former top executives, Jeffrey K. Skilling and Kenneth L. Lay. “The texting, twittering, BlackBerry-toting jurors of today understand that an e-mail capturing a concern, doubt or momentary distress does not reflect thought over time, much less a vetted public statement.”

One of the main documents in the case was an e-mail message that Mr. Tannin sent from his private Gmail account to the e-mail account of Mr. Cioffi’s wife. He wrote that the subprime market  the market to which the funds were tied  “looked pretty damn ugly,” and that if a recent report was correct, “then the entire subprime market is toast.” Days later, during a conference call, Mr. Tannin told investors that “we’re very comfortable with exactly where we are.”