Federal regulators are poised to sue Jon S. Corzine over the collapse of MF Global and the brokerage firm's misuse of customer money during its final days, a blowup that rattled Wall Street and cast a spotlight on Mr. Corzine, the former New Jersey governor who ran the firm until its bankruptcy in 2011.
The Commodity Futures Trading Commission, the federal agency that regulated MF Global, plans to approve the lawsuit as soon as this week, according to law enforcement officials with knowledge of the case. In a rare move against a Wall Street executive, the agency has informed Mr. Corzine's lawyers that it aims to file the civil case without offering him the opportunity to settle, setting up a legal battle that could drag on for years.
Without directly linking Mr. Corzine to the disappearance of more than $1 billion in customer money, the trading commission will probably blame the chief executive for failing to prevent the breach at a lower rung of the firm, the law enforcement officials said. If found liable, he could face millions of dollars in fines and possibly a ban from trading commodities, jeopardizing his future on Wall Street.
In a statement, a spokesman for Mr. Corzine denounced the trading commission for planning to file what he called an "unprecedented and meritless civil enforcement action."
The aggressive action would stand in contrast to the government's investigations so far into the 2008 financial crisis, many of which produced symbolic fines. In the case of Lehman Brothers, which imploded at the height of the crisis, no employee has ever been charged with civil or criminal wrongdoing.
An MF Global case, expected to be filed in federal court, could become something of an experiment for federal regulators under pressure to adopt a harder line against Wall Street. It would also thrust the trading commission — the financial industry's smallest regulator — onto a bigger stage.
A case would darken the cloud over the legacy of Mr. Corzine, 66, who as a onetime Democratic governor and senator from New Jersey and a former chief of Goldman Sachs has long been a confidant of leaders in Washington and on Wall Street.
But it would also suggest that authorities have all but removed a greater threat: criminal charges. After nearly two years of stitching together evidence, criminal investigators have concluded that porous risk controls at the firm, rather than fraud, allowed the customer money to disappear, according to the law enforcement officials with knowledge of the case.
Still, the spokesman for Mr. Corzine, Steven Goldberg, said that the trading commission's anticipated lawsuit "is not surprising considering the political pressure to hold someone liable for the failure of MF Global," the largest Wall Street bankruptcy since the 2008 financial crisis. Lawmakers and even some agency officials, he noted, have publicly condemned the firm.
"If the C.F.T.C. brings this enforcement action, Mr. Corzine would welcome the opportunity to litigate this matter in an impartial venue, free from politically influenced prejudice and unfounded assertions, which have been frequently repeated despite the lack of a factual basis," Mr. Goldberg said.