American International Group Inc. (AIG) staunched the flow of investment losses to turn its first profit in six quarters, but its core insurance operations are still struggling to rebuild.

Shares were recently up 4.8% at $23.60 in premarket trading. The stock through Thursday was already up 71% this week.

Chairman and Chief Executive Edward Liddy said the results "reflect stabilization in certain of our businesses" and were driven by lower net realized capital losses.

"While our insurance companies' operating results remain challenged, largely driven by weak economic conditions and the lingering effect of negative AIG events earlier in the year, performance trends stabilized from the first quarter," he went on to say. Liddy added that the company expects volatility in its results to continue in the coming quarters, partly because of charges related to restructuring.

The results in its insurance operations - lower premiums and a smaller underwriting profit, gives some support to claims by competitors that AIG is cutting prices in order to keep business, creating an unfair disadvantage for insurers that do not receive government support.

AIG - which is 80% owned by the U.S. government following its rescue of the company last September - posted income of $1.82 billion, or $2.30 a share, compared with a year-earlier loss of $5.36 billion, or $41.13 a share. Excluding capital losses and other items, earnings were $2.57 a share, compared with a prior-year loss of $10.15 a share.

Revenue jumped 48% to $29.53 billion.

Operating income at AIG's general-insurance business dropped 19% on a decline in underwriting profit, while net premiums written fell the same amount. Combined ratio, or the portion of premiums paid out on claims and expenses, rose six percentage points to 98.2%.

Meanwhile, the life-insurance and retirement-services segment's loss narrowed sharply as the company said it had a difficult but improving operating environment.

On Monday, Robert Benmosche, the former chairman and chief executive of MetLife Inc. (MET), will step in as AIG's new chief executive, and new director Harvey Golub, formerly chief executive of American Express Co. (AXP), takes over as non-executive chairman. Edward Liddy, who took both roles in September after AIG's first bailout, will step down.

-By Lavonne Kuykendall and Kerry Grace Benn, Dow Jones Newswires; (312) 750 4141; lavonne.kuykendall@dowjones.com