Citigroup Inc, the largest bank in the US, which suffered a $15 billion net loss over the last two quarters, and reported more than $45 billion of write-downs and credit losses since 30 June last year, plans to raise $3 billion through sale of common stock.

Citigroup said it had received "strong" interest in the public offer. The company may increase the issue size depending on the market response, chief financial officer Gary Crittenden said in a statement.

Citigroup has so far raised more than $36 billion in capital, including last week's sale of $6 billion of preferred stock, since late 2007.

The bank also sold $12 billion in leveraged loan portfolio this month to private equity investors to raise funds.

Citigroup stock has risen 46 per cent from a low of $18 on 17 March, a level not seen since October 1998, on expectations that the worst of the write-downs may have passed.

The offer, the first in Citigroup's recent capital-raising to involve common stock, is expected to dilute promoter holding in the bank, said an analyst, adding, it is a better option than paying a high premium in a preferential issue .

Citigroup plans to sell the stock on Wednesday, the day when the US Federal Reserve is also expected to announce a cut in interest rates.

Citigroup has so far reported over $40 billion in credit losses and writedowns since the subprime mortgage market collapsed last year.

Citigroup stock fell 80 cents, or 3 per cent, to $25.52 in after-hours electronic trading. They had fallen 49 cents during regular trading. Citigroup's market value is about $138 billion, based on the closing price and reported shares outstanding as of 31March.

Citigroup said the current stock sale, together with its recent preferential issue, will leave its Tier-1 capital ratio as of 31 March at 8.5 per cent on a pro forma basis. The bank had reported 7.7 per cent Tier-1 capital adequacy ratio as of 18 April.

Other US banks, including Bank of America Corp, Wachovia Corp, Washington Mutual Inc and National City Corp, are raising capital this month. Top global banks have together raised over $170 billion to replenish their capital.

JPMorgan Chase & Co., the third-biggest US bank by assets, and Merrill Lynch & Co, the third-largest securities firm, also have raised capital in recent weeks through sale of preferential stock.

Chief executive Vikram Pandit and Crittenden had, earlier this year, said that Citigroup might avoid the need to raise more capital.