When Apple announced its second-quarter earnings on Tuesday, what really got the Internet buzzing was the fact that its mountain of cash grew 13 per cent year on year to a new record of US$261.5 billion (S$355 billion).

In comparison, Singapore's gross domestic product for last year was $410.3 billion. So Apple's cash reserves are as much as 87 per cent of Singapore's economic output.

Put it another way, Apple could buy tech-based companies - Uber, Tesla, Netflix, Airbnb, and Twitter - and still have US$29 billion left over, said CNBC.

This is thanks to years of huge profits from selling iPhones, iPads and apps from its store.

Apple has made few big acquisitions, other than investments in Didi and Beats.

Instead, the company spends a few billion each quarter on fuel research and development.

The US tech giant stashes most of its cash overseas where the the money is not subject to US taxes.

Chief financial officer Luca Maestri told analysts on Tuesday that US$246 billion of Apple's cash, or 94 per cent of the total, was outside the United States.

CNN reported that non-financial US companies piled up US$1.84 trillion of cash at the end of last year, based on research by credit ratings agency Moody's. That's up 11 per cent from 2015 and nearly 21/2 times the 2008 level.

The top five hoarders were all tech companies - Apple, Microsoft, Google parent Alphabet, Cisco and Oracle.

US President Trump is hoping to change all that with his promise to pass tax reform that will include a tax holiday to encourage companies like Apple to bring their cash pile home.

Proponents of a tax holiday argue that bringing the money home could boost the US economy with companies using the cash to hire and invest.

But critics say the real economy may not see much of a boost because many companies would use the money instead to reward shareholders with dividends and stock buybacks.