Billionaire investor Warren Buffett has made a huge bet on Apple while dumping almost all of his stock in Asda owner Walmart.

The 86-year-old, worth an estimated £60bn, nearly quadrupled his stake in Apple late last year, raising his company’s holding from 15.2m shares to 57.4m.

The iPhone maker’s shares hit a record high yesterday of $136.27 (£109.49) making his stake worth £6.3bn.

Planning ahead: Warren Buffett, worth an estimated £60bn, nearly quadrupled his stake in Apple

His firm Berkshire Hathaway also offloaded £723m of Walmart stock – a shift some will view as an admission the industry is in decline.

The American dubbed the Sage of Omaha has focused on the threat from online retailers such as Amazon.

Buffett told shareholders in Omaha last year: ‘It’s a big force and it has already disrupted plenty of people and it will disrupt more.’

The tycoon also upped his stakes in airline companies, including £1.7bn in each of American Airlines Group, Delta Air Lines and Southwest Airlines and United Continental Holdings.

The new, larger stake in Apple makes Berkshire one of the technology giant’s ten biggest investors.

The California-based company is thought to be on the brink of releasing a radically redesigned new iPhone.

Elsewhere in technology, Twitter founder Jack Dorsey bought £5.6m of shares in the ailing social media giant. He tweeted his regulatory filing, adding ‘#LoveTwitter’ – demonstrating his confidence in the company.