Why more of this creeping incrementalism? If the banks are in such bad shape that they need U.S. ownership to stay afloat, isn't that pretty much the time to stop the charade? When even Alan Greenspan is saying to nationalize the banks, isn't it time to actually, you know, do it?

Citigroup Inc. is in talks with federal officials that could result in the U.S. government substantially expanding its ownership of the struggling bank, according to people familiar with the situation.

While the discussions could fall apart, the government could wind up holding as much as 40% of Citigroup's common stock. Bank executives hope the stake will be closer to 25%, these people said.

Any such move would give federal officials far greater influence over one of the world's largest financial institutions. Citigroup has proposed the plan to its regulators. The Obama administration hasn't indicated if it supports the plan, according to people with knowledge of the talks.

When federal officials began pumping capital into U.S. banks last October, few experts would have predicted that the government would soon be wrestling with the possibility of taking voting control of large financial institutions. The potential move at Citigroup would give the government its biggest ownership of a financial-services company since the September bailout of insurer American International Group Inc., which left taxpayers with an 80% stake.

The talks reflect a growing fear that Citigroup and other big U.S. banks could be overwhelmed by losses amid the recession and housing crisis. Last week, Citigroup's share price fell below $2 to an 18-year low. Bank executives increasingly believe that the government needs to take a larger ownership stake in the institution to stop the slide.

Under the scenario being considered, a substantial chunk of the $45 billion in preferred shares held by the government would convert into common stock, people familiar with the matter said. The government obtained those shares, equivalent to a 7.8% stake, in return for pumping capital into Citigroup.

The move wouldn't cost taxpayers additional money, but other Citigroup shareholders would see their stock diluted. A larger ownership stake by the government could fuel speculation that other troubled banks will line up for similar agreements.