RSA Insurance Group Plc was upgraded by Standard & Poor’s after Chief Executive Officer Stephen Hester announced a stock sale and a deal to transfer risk to Warren Buffett’s Berkshire Hathaway Inc.

The credit grade was lifted to “A” from “A-,” reflecting “our expectation of a material improvement in RSA’s prospective balance sheet,” the ratings firm said in a statement on the London-based insurer.

Hester, former CEO of the Royal Bank of Scotland Group Plc, joined the insurer last month to help restore confidence after the company needed to inject capital in an Irish unit amid an accounting probe. On Feb. 27 he announced a 775 million pound ($1.3 billion) share sale and halted the dividend. Berkshire agreed to provide a 550 million pound reinsurance policy to guard against higher-than-expected losses.

The CEO’s plan, and efforts to dispose of some units, may increase the volatility of results, according to S&P. The ratings firm estimated that net income will exceed 200 million pounds this year and 320 million pounds in 2016 while saying “there is likely to be a period of uncertainty around our capital and earnings forecasts.”

Chief Financial Officer Richard Houghton welcomed the upgrade as an endorsement of the company’s plan, according to a separate statement from RSA.