A former star investment banker with Credit Suisse First Boston has been charged in the United States with obstructing justice and destruction of evidence.
US federal prosecutors arrested Frank Quattrone on Wednesday following an investigation into claims he engaged in corrupt behaviour designed to win the bank business.
Quattrone resigned from CSFB last month amid mounting legal pressure.
The obstruction of justice charge stems from an email Quattrone is alleged to have sent to staff during a December 2000 investigation by the Wall Street regulator, the National Association of Security Dealers (NASD).
The Manhattan Attorney, James Comey, said: "The complaint alleges that an important banker at a very important firm decided to encourage his subordinates to clean out their files."
Comey added that Quattrone did this even though he knew that a grand jury and the US Securities and Exchanges Commission (SEC) had asked for documents that were in those files.
According to news reports, Quattrone's email was entitled "Time to clean up those files" and was sent just two days after a CSFB lawyer notified the 47-year-old of the investigation.
Quattrone was released on bail following his arrest.
Plea of innocence
John Keker, the former banker's lawyer, said his client was innocent.
"He never obstructed justice," Keker said. "The only way we can prove that is to try this case, which is why we will ask that the jury trial occur at the earliest possible moment."
During the 1990s dotcom boom, Quattrone became one of Wall Street's highest-paid figures, earning almost $100 million (SFr138 million) a year.
He also wielded enormous influence as head of CSFB's California-based technology unit, which presided over lucrative initial public offerings (IPOs) for firms such as Amazon.com and Netscape Communications Corp.
In 2000, when the technology bubble burst, regulators began scrutinising the bank's IPO practices.
The bank paid $100 million in late 2001 to settle accusations by the NASD and the SEC that it had charged inflated commissions to some clients in exchange for access to IPO shares.
CSFB was forced to pay another $200 million at the end of last year as part of an industry-wide settlement over conflicts of interest between stock research and banking.
Last month, the NASD charged Quattrone with tipping off clients about forthcoming IPOs, as well as undermining the objectivity of research analysts.
A CSFB spokeswoman said the bank had no comment on Quattrone's case.
swissinfo with agencies