As well as being the world's largest mutual fund firm, Fidelity Investments is now Apple's biggest shareholder.

Bloomberg News writes that the firm boosted its shares in the company by 9.53 million shares in the fourth quarter, bringing its stake in Apple to 5.2 per cent.

A filing with the Securities and Exchange Commission states that Fidelity's 21.1 million Apple shares were worth about $1.36 billion at the end of last year.