Octogenarian billionaire Warren Buffett said Saturday that his Berkshire Hathaway empire, with holdings in major American financial firms, is ready for his departure as well as that of his longtime partner Charlie Munger, aged 96.

Dubbed the "Oracle of Omaha," Buffett is known for his track record of brilliant investing but also for his folksy and humble persona, as well as his philanthropy.

"Charlie and I long ago entered the urgent zone," Buffett, 89, quipped in his annual letter to shareholders.

"That's not exactly great news for us. But Berkshire shareholders need not worry: Your company is 100 percent prepared for our departure."

Buffett, the world's third-richest man, did not go into detail or name a successor.

Warren Buffett is known for his track record of brilliant investing but also for his folksy and humble persona, as well as his philanthropy. Warren Buffett is known for his track record of brilliant investing but also for his folksy and humble persona, as well as his philanthropy. Photo: AFP / Johannes EISELE

At an annual shareholders meeting last May, he gave a clue as to who might follow him, when he said that Gregory Able and Ajit Jain would in the near future join him and Munger on the stage to answer shareholders' questions.

Able, 57, and Jain, 67, had been promoted to the board of directors the previous year.

"Charlie and I have very pragmatic reasons for wanting to assure Berkshire's prosperity in the years following our exit," Buffett said in the letter published Saturday.

"The Mungers have Berkshire holdings that dwarf any of the family's other investments, and I have a full 99 percent of my net worth lodged in Berkshire stock."

Buffett added that he has never sold any shares -- and has no plans to do so.