Berkshire Hathaway CEO Warren Buffett says the company’s board has unanimously decided on a successor ­but it’s too early to say exactly who that person might be.

Mr Buffett, 75, is regarded as one of the best investors in the US, and owns several global reinsurance companies.

But even as the speculation over who his successor might be had the US financial media slavering late last week, Mr Buffett was dealing with a new challenge: his tradition of releasing his annual letter to shareholders over a breakfast meeting on a Saturday may soon end after a new US regulator rule requiring faster disclosure.

It is expected the US Securities and Exchange Commission rule will require the company’s annual report and letter to the shareholders to be released during a week day as opposed to a Saturday, allowing eager investors to garner Mr Buffett’s thoughts earlier.

Mr Buffett says more acquisitions are needed to improve Berkshire Hathaway’s earnings in future years.

Net income for the full year increased 17% to $US8.53 billion ($11.45 billion).