Credit Suisse First Boston

reportedly agreed to pay $100 million to settle allegations that it received kickbacks from clients in return for allocation of IPO shares at the height of the Internet IPO frenzy.

The Credit Suisse Group unit agreed to the payment following an 18-month probe by federal investigators, who decided earlier this month not to bring criminal charges against the investment bank. The settlement is the fifth-largest ever leveled by the U.S. government on a securities company.

CSFB, which won't admit or deny guilt, reportedly received more than $700 million in fees from Internet IPO underwriting, more than any other firm. According to

The Wall Street Journal

, the company will probably be formally alleged to have improperly shared IPO profits and to have committed bookkeeping violations.

According to the story, following formal announcement of the CSFB settlement, securities regulators are expected to issue new rules on how IPO shares are allocated to Wall Street customers. The rules will be designed to encourage broader distribution of such shares and place limits on deals favoring certain clients.

Several other Wall Street firms are still under investigation for allegedly allocating IPO shares to customers who agreed to buy more of the same stock once it started trading. According to the

Journal

, that probe focuses on

Goldman Sachs

(GS) - Get Report

,

Morgan Stanley Dean Witter

(MWD)

,

J.P. Morgan Chase

(JPM) - Get Report

and the Robertson Stephens unit of

FleetBoston

(FBF)

.