-source@ (Adds background on AIG bailout)
WASHINGTON, Nov 10 (Reuters) - Global financial regulators have decided to ditch a "too big to fail" gauge for assessing the riskiness of insurers, according to a source briefed on the matter, in a big win for companies such as American International Group and Prudential Financial Inc .
The Financial Stability Board (FSB), which coordinates financial regulation across the Group of 20 Economies (G20), is expected to announce in coming weeks a switch in focus from insurers' size to their activities when deciding whether to subject them to increased regulatory scrutiny, said the source, who requested anonymity because the matter has not been made public.
Companies singled out for such scrutiny are required to hold extra capital to cover potential losses, increasing overall business costs and potentially reducing shareholder returns.
The insurance industry has been lobbying for years for regulators to move to the activities-based approach, arguing that their huge size should not automatically qualify them as systemically risky and on the hook for onerous bank-like capital rules.
The shift in the FSB's approach to designating globally systemically important insurers, or GSIIs, follows pressure from the U.S. Treasury Department, which has been pushing the FSB to ease up on insurers and asset managers, the source said.
A spokesman for the FSB declined to comment.
The administration of President Donald Trump has pledged to overhaul regulations introduced following the 2007-2009 global financial crisis and put U.S. interests first when engaging in international bodies such as the FSB and the Basel Committee of banking supervisors.
In September, a group of U.S. regulators - known as the Financial Stability Oversight Council - removed AIG from its domestic list of systemically important insurers, raising questions over whether the FSB would keep AIG on its global list and continue to add new firms.
In a policy report published last month, the U.S. Treasury rejected the idea of singling out specific asset management and insurance firms as systemically risky and criticized the FSB for mission-creep and a lack of transparency.
The U.S. Treasury is shortly due to release a policy report on the FSOC designation process and powers, which critics including regulatory experts and insurers have said are too opaque and unaccountable.
AIG helped spark the global financial crisis, and the labeling of major financial institutions as systemically important stems largely from its $182 billion U.S. government-led rescue in September 2008. The bailout came just before the company would have been forced to file for bankruptcy protection amid mounting losses on its derivatives book.
Worried the insurance giant was too big to fail, the government stepped in to prevent further chaos to the financial system. The company ultimately repaid taxpayers in full by the end of 2012, with a profit of $22.7 billion, according to AIG.
Since then, regulators have primarily focused on the size of a company's overall assets when assessing the risk they pose to the global financial system.
Moving to an activities-based approach could see firms on the list that largely engage in traditional insurance activities removed, but other non-designated insurers that use their cash to invest in risky assets, or which deploy high levels of leverage, added.
The suspension of the 2017 review means the 2016 list of nine GSIIs - which also includes MetLife Inc, Allianz SE and Ping An Insurance Group Co of China Ltd - will continue to stand for at least the next 12 months until the FSB has completed an assessment based on the new methodology, the source said. (Reporting by Michelle Price and Pete Schroeder; Additional reporting by Huw Jones in London; Editing by Tom Brown)