Daniel Calugar, the mutual fund trading scandal's enduring man of mystery, may end up owing more to regulators than almost any of the saga's other players -- a cast that includes several banks and hedge funds.

Calugar, a tax attorney turned broker, could be ordered by regulators to pay as much as $570 million in fines and restitution for his part in the far-reaching scandal. The $570 million includes the highest possible fine the SEC could impose in the matter. New York Attorney General Eliot Spitzer also is investigating Calugar's trading, a person familiar with the inquiry says.

The SEC, in a recent court filing in the year-old civil case, now estimates Calugar's ill-gotten trading gains at $285 million, up from an initial $175 million. But the SEC notes the amount could be even higher because it's still reviewing the trading records of Calugar's now-defunct Las Vegas firm,

Security Brokerage

.

At the end of the day, Calugar is looking at a stiffer monetary sanction than just about any individual mutual fund family, brokerage or hedge fund that's been linked to the scandal, which so far has netted $3 billion in fines, restitutions and fee reductions.

To date, the biggest settlement in the mutual fund scandal is a $675 million joint payout by

Bank of America

(BAC) - Get Report

and

FleetBoston

, which was acquired by BofA earlier this year. Other substantial payouts include the $600 million shelled out by

Alliance Capital

(AC) - Get Report

; the $450 million regulatory tab agreed to by

Invesco/AIM Advisors

, a division of

Amvescap

( AVZ); and the $350 million paid out by

Massachusetts Financial Services

, a division of

Sun Life Financial

(SLF) - Get Report

.

The top penalty assessed against an individual is $80 million, a sum agreed to last month by former investment advisers Harold Baxter and Gary Pilgrim.

Of course, what makes the potential regulatory action against Calugar even more astonishing is the fact that he's hardly a household name on Wall Street. Before the SEC charged him with securities fraud, few in the shady world of mutual fund market-timers and late-traders had ever heard of Calugar.

As

TheStreet.com

first

reported in February, Calugar's biggest claim to fame before the SEC action had been a brief appearance on a CBS national news program in 1994 focusing on "millionaire bachelors" looking for love. On the show, Calugar talked about a personal ad he had placed in

New York

magazine, offering to pay $100,000 to "the person who introduces me to the woman I marry."

Yet somehow, working with fewer than a handful of employees, Calugar managed to turn his Security Brokerage outfit into the mutual fund equivalent of a Wall Street boiler room. Regulatory records reveal that the small brokerage, established in 1996, never had any retail customers and did little, if any, stock trading.

The most recent SEC court filings continue to reveal little about Calugar the man, but they reveal new details about his illicit activities.

In particular, Calugar was a far more prolific late-trader than previously thought. The SEC has identified 8,152 after-hours mutual fund trades made by Calugar from March 30, 2001, through September 2003.

In the mutual fund investigation, late-trading has emerged as the most serious offense, which some prosecutors have treated as a criminal offense. Late-trading involves buying shares of a mutual fund after their 4 p.m. closing price in order to take advantage of late-breaking, market-moving news.

Calugar also was a big market-timer, someone who made frequent trades in mutual fund shares to capitalize on price discrepancies in different markets.

While market timing is legal, it is harmful to long-term investors because it increases the administrative costs for a fund. Regulators have brought enforcement actions against mutual fund families for violating their obligations to their shareholders by entering into secret market-timing deals with some traders. The SEC has alleged that Calugar negotiated a number of these deals with Alliance and

Franklin Resources

(BEN) - Get Report

, parent company of the Franklin/Templeton funds.

But it appears late-trading may have accounted for more of Calugar's enormous profits than anything else. Calugar's attorney, Steven Scholes, did not return several phone calls.

In the end, the penalty Calugar pays ultimately may depend on just how much money he has stashed away, and whether regulators can locate all his assets.

Last December a federal judge initially granted an SEC request to freeze $532 million in assets that Calugar had in various brokerage and mutual fund accounts. But the judge recently reduced that amount to $450 million. The judge took the action, even though he ruled that the SEC is likely to prevail in its civil action against Calugar.