The world's largest mutual fund company Fidelity Investments has increased its stake in Apple stock, regulatory filings reveal.

Fidelity's purchase of 2.9 million additional shares brings the company's Apple holding to 58 million shares – or 6.7 per cent of the total stock issue.

Wellington Management Company also raised its Apple stake, acquiring 20 million shares to give it a 2.3 per cent stake in the company, Bloomberg reports.

Both stock acquisitions took place before share values climbed in excess of $100 each. The investors believe the release of the iPhone later this year will boost Apple's sales.

Fidelity also purchased 22 million shares in Flash memory manufacturer, Sandisk, along with 122 million shares of Sun, Bloomberg explains.