Do you invest with your head or with your heart?

The parents of Jeff Bezos evidently did both back in 1995 when they contributed $245,573 – a big chunk of their retirement fund – into his year-old online bookstore Amazon.

Twenty-three years on, Jeff, 54, is the world’s richest person with a fortune of $150bn after surpassing Microsoft’s Bill Gates. He has added an incredible $77bn in just 16 months.

Now, with Amazon’s stock market value at an all-time high of $917bn after the eCommerce giant’s quarterly profit topped $2bn for the first time, Mike and Jackie Bezos must be quite glad that they bet on their son.

While the number of shares they still own has not been public since 1999, it has been estimated at around 16.6 million – 3.4 per cent of the company – which would be worth $29.6bn, or £22.5bn, according to Bloomberg.

Jeff’s brother Mark and sister Christina are also in the money: the 30,000 shares they bought for $10,000 in 1996 could now be worth around $640m (£487m).

Their parents have reportedly donated 595,027 shares to the Bezos Family Foundation, which provides education for young people, in the past. According to Bloomberg, the 25,000 they donated in 2016 were worth about $20m at the time.