Royal Bank of Scotland (RBS) has left the government's asset protection scheme which guarantees against losses from banks' riskiest assets.
The insurance set up was established in 2009 and would have seen taxpayers absorb any losses.
In a notice to the stock exchange, RBS said it had paid £2.5bn to participate in the scheme but made no claims. It said it was in addition to the £1.5bn it paid to the Treasury for liquidity support during the financial crisis.
The bank explained the government scheme provided backstop credit insurance for a portfolio of RBS assets and derivative exposures.
The statement said: "It played an important role in stabilising market perceptions of RBS after the impact of the financial crisis became clearer and the bank's share price fell to a low of 10 pence in February 2009.
"This gave time for the bank's new board and management to put its recovery plan into effect."
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