Warren Buffett has stepped down as chairman of Berkshire Hathaway, handing over leadership to his son Howard in the final chapter of a long-planned transition at the US business giant.

At 96, the world-famous investor will move into an advisory role as chairman emeritus and remain on the company board to offer his "judgement and perspective", according to a letter to shareholders.

The decision comes nine months after Buffett passed the chief executive role to Greg Abel, with his son, Howard, who has been a director since 1993, taking over non-executive board duties.

Known as the "Oracle of Omaha," Buffett built one of the most successful investment track records in modern history.

He took control of Berkshire Hathaway in 1965 when it was a struggling New England textile mill and turned it into a $1.1 trillion (£822b), global conglomerate.

Today, the business owns a wide range of well-known brands including GEICO car insurance, Dairy Queen, and BNSF railway system. It also owns large stakes in companies like Apple and Coca-Cola – a brand close to Buffett's heart, as he famously drinks five cans a day.

Buffett has made his mark through "value investing" – a strategy focused on finding companies with solid fundamentals, buying them at fair prices, and holding them for decades.

His annual letters to shareholders and festival-like annual meetings turned him into a leading mentor across the financial world.

Despite his retirement from the top board post, the change is considered an orderly passing of the baton rather than a sudden shock.

"The timing is right to complete the transition," Buffett wrote, noting he had recently celebrated his 96th birthday and the first birthday of one of his great-grandchildren, who is "moving a bit faster" than he is.

The company assured investors that day-to-day operations will remain steady.

While Greg Abel manages corporate strategy and capital decisions, Howard Buffett's main duty as chairman will be guarding the firm's "culture and values". A former farmer, philanthropist, and sheriff, the younger Buffett brings more than three decades of board experience to the role.

Buffett concluded his letter by saying it had been the "privilege of a lifetime" to serve as chairman, but acknowledged that in the end, "Father Time always wins".