NEW YORK (MarketWatch) -- Frank Quattrone hailed a decision Monday by a U.S. appellate court to overturn his conviction for obstruction of justice.

"For over three years during this difficult ordeal, I have held my head high knowing I was innocent and never intended to obstruct justice," Quattrone said in a statement.

A day later, many legal analysts say Quattrone should enjoy his victory while he can. Chances are strong that federal prosecutors will try the former investment banker for a third time, despite looming obstacles.

Quattrone's 2004 conviction for obstruction of justice was overturned Monday by the 2nd U.S. Circuit Court of Appeals on the grounds that jury instructions in the star banker's second trial were inappropriate. Quattrone was accused of ordering the destruction of documents while his firm, Credit Suisse First Boston, was under subpoena.

A first trial of Quattrone ended in a hung jury in October 2003.

"It's hard to see a Mr. Quattrone throwing in the towel at this point," said C. Evan Stewart, a securities law defense attorney with Zuckerman Spaeder. "He has the resources to fight."

Stewart, who was the lead trial attorney for acquitted mutual fund late-trader Theodore Siphol, acknowledged that a third trial will create tremendous expense and effort for prosecutors -- many of whom weren't part of the team that worked on the case four years ago. But, to let Quattrone go, would be to go against unwritten prosecutorial codes.

"They've tried it twice and had virtually everyone in that jury box in agreement," he said. "If you're sitting here as a taxpayer you're saying 'wait a minute.' But the cost of these things really doesn't go into how the government thinks about it."

A third trial will require the government to spend millions of dollars and hundreds, possibly thousands of hours, to prosecute Quattrone. The banker was sentenced to 18 months after his conviction in the second trial but didn't serve any time while the case was appealed.

The U.S. Attorney's Office has declined to comment on the appellate decision saying only that it is considering its options.

Since Quattrone's conviction in 2004, the legal landscape has changed. Most notably, the U.S. Supreme Court overturned the conviction of the accounting firm Arthur Andersen LLP on obstruction of justice charges, citing errors in the original court proceedings including improper jury instructions.

Sending a message

However, some believe prosecutors will wave off the costs, time and energy required for a third trial in order to send a message to Wall Street.

"Prosecutors look for cases that have the most impact," said Stuart Meissner, a former New York assistant attorney general in the investor protection and financial crimes bureau. "They do seek to make examples of people. If they believe the policy they pursued originally still matters today...they want to encourage compliance."

pliance." Not everyone agrees, however. Jack Silvia, a defense attorney with Mintz Levin in Boston, said the public has tired of Internet-era scandals and there is substantial risk Quattrone could be acquitted.

"This is not the crime of the century," he said. In 2003, "a lot of people were still smarting from the dot-com implosion. People were very focused on whether the system was giving them a fair shake."

In addition, Silvia believes a new judge might allow Quattrone's attorneys to present new evidence that the original judge in the case blocked. Silvia believes the first conviction was not a slam-dunk case.

"On the other hand," he said. "We're talking about a U.S. Attorney's office that has a history of not letting go of things."

A third alternative might be a plea agreement, according to Sean O'Shea, a former federal prosecutor for securities fraud now in private practice.

"There's an option for both sides to save face," he said. "It's tough road (for prosecutors) and I think they have to think hard about what they want to do."

David Weidner covers Wall Street for MarketWatch.