Simpson Thacher & Bartlett is advising the US Treasury on its plan to unload 7.7 billion government-owned Citigroup shares in a series of sales rather than all at once, reports The Am Law Daily.

The US Government has retained Morgan Stanley to prepare the sale and place the initial batch of 1.5 billion Citi shares on the market, with Davis Polk & Wardwell and Cleary Gottlieb Steen & Hamilton sharing the job of advising Morgan Stanley.

M&A partner Lee Meyerson and corporate partner Andrew Keller are leading the Simpson Thacher team, while corporate partner Jeffrey Karpf is heading up the Cleary team.

Davis Polk and Cleary have are advising longstanding client Citi on its bailout-related negotiations with the Treasury, including representing Citi on the Treasury's deal to acquire an equity stake in the ailing bank and Citi's subsequent move to repay the Government $20bn (£13bn) in bailout funds.

Davis Polk advised Morgan Stanley on the terms of its work for Treasury, including the bank's compensation. Under those terms, Morgan Stanley will receive $0.003 (£0.002) for each share it sells via electronic trading systems. That is below the market rate for underwriters on large equity sales, but Morgan Stanley is placing the sales on the market rather than buying them in principle, as is typical in stock offerings.

The sheer size of the full offering – which will total 7.7 billion shares over the course of 2010 – means Morgan Stanley stands to earn as much as $123m (£80m) for its work. Davis Polk also worked with Morgan Stanley to come up with the idea of a gradual stock sale, after which Cleary took over in preparing the offering itself.

Simpson Thacher won its role to advise the US Treasury early in the bailout process after a six-firm beauty contest in late 2008. Four firms told the Treasury they were not interested in the work, including Davis Polk and Cleary, amid concerns that the Treasury's conflicts requirements were overly strict.

Simpson Thacher's initial contract called for it to be paid just $300,000 (£195,000) over its first six months of work. Richard Beattie, the firm's chair, dismissed the concern over Treasury's rules for conflicts and called the assignment "an honour."

The Am Law Daily is the website of The American Lawyer, Legal Week's US sister title.