The United States government could make a profit of $15.1 billion from the bailout of insurance giant American Insurance Group Inc (AIG) during the global financial crisis, the Government Accountability Office (GAO) said Monday in its latest report.

The gains have come through the sale of AIG shares, which the treasury acquired as well as the troubled mortgage securities which the federal reserves obtained during the unprecedented financial meltdown in 2008.

''Based on the composition of the remaining federal assistance to AIG, the repayment and recovery progress thus far on all assistance, the government could receive total returns of approximately $15.1 billion in excess of the assistance provided, including interest, dividends, and fees,'' GAO, the congressional watchdog agency said.

Since September 2008, the treasury and the federal reserves injected over $180 billion in a complicated, multi-step bailout to save the ailing insurer in one of the government's largest investments in the private sector. The treasury shelled out around $125 billion for picking a 92-per cent stake in AIG.

The actual size of the gain could depend on the long-term financial health of the insurer and treasury's timing of the stake sale.

The study also said that the gains estimated do not reflect the subsidy costs associated with the financial aid.

Earlier on Sunday, the treasury announced that it would sell AIG stake worth $5 billion or 164 million shares at $30.50 per share.

Subsequently, on Monday it further decided to sell additional 24.6 million shares for $750 million.

The sale has become profitable as AIG shares rose 41.5 per cent year-to-date. The shares closed at $31.70 on Tuesday in New York.

Total proceeds through the two sales are estimated to be around $5.8 billion, bringing down the treasury's investment in AIG to around $30 billion.

Federal reserves will still have an investment of $9 billion in the insurer.

Through the current sale, the government's ownership stake in AIG has come down to 61 per cent from 70 per cent.

The government believes that it can recover in full the taxpayers' money injected into AIG. AIG has been steadily repaying the debt by buying treasury shares and selling of some of its non-core assets.

During the past one year, the treasury has sold two lots of AIG shares, the first sale in May 2011 brought in $5.8 billion, while the second sale in March 2012 fetched $6 billion.

According to the GAO study, AIG was becoming ''stable and profitable.'' Its net income for 2011 was $18.5 billion augmented by tax benefits and asset sales. For the first quarter, the company reported a net income of $3.2 billion, up from $1.3 billion for the same period a year ago.

New York-based AIG has presence in more than 130 countries. Its segments SuAmerica Inc, which sells retirement annuities and ILFC which leases aircraft, sells aircraft engines and parts have strong presence in California.