Carl Icahn ups his bullish bet on Apple Inc. as he increased his stakes on the company from 2.8 million shares to more than 7.5 million shares - amounting to $1.65 billion.

Mr Icahn's recent position was revealed in a Securities and Exchange Commission filing on Thursday, AppleInsider reports.

According to the SEC filing, Icahn's bullish buy was placed during the March period ahead of Apple Inc's announcement of its second quarter results and the controversial 7-to-1 stock split and $130 billion repurchase programme.

Apple announced quarterly revenue of $45.6 billion and quarterly net profit of $10.2 billion, or $11.62 per diluted share. Around the same quarter of 2013, the company announced $43.6 billion and net profit of $9.5 billion or $10.09 per diluted share. The company's gross margin was 39.3 per cent compared to 37.5 percent in the year-ago quarter and international sales accounted for 66 per cent of the quarter's revenue, according to a statement from Apple Australia.

"We are announcing a significant increase to our capital return program. We're confident in Apple's future and see tremendous value in Apple's stock, so we're continuing to allocate the majority of our program to share repurchases. We're also happy to be increasing our dividend for the second time in less than two years," CEO Tim Cook said in a statement.

"We generated $13.5 billion in cash flow from operations and returned almost $21 billion in cash to shareholders through dividends and share repurchases during the March quarter. That brings cumulative payments under our capital return program to $66 billion," CFO Peter Oppenheimer, Apple's CFO.

Following Apple's announcement, Icahn expressed his delight through a Tweet, saying he is extremely pleased with the company's revenue and decision to increase its buyback plan. He also said that Apple stock remains meaningfully undervalued as many analysts fail to understand the company.

Icahn had always been passionate in convincing Apple to increase its increase of the share-repurchase programme by $50 billion. He gave up his plea in February as he also withdraw his prodding for Apple to increase its debt to fund its supposedly $50 billion buyback.