Sir Michael Moritz, a leading partner in the American venture capital firm Sequoia Capital, has been named as one of the few billionaires who have earned their wealth through technology, according to the Sunday Times' Super-Rich List.

Just four out of the list of 100 billionaires in the UK and Ireland have made their riches from technology. Except for Moritz, the other three billionaires have mobile phones to thank for their wealth.

Sequoia Capital

Cardiff-born Moritz is chairman of Sequoia Capital, which provides seed, early and growth stage investment for emerging technology companies across the world.

Valued at £1.69 billion, the 59-year-old he ranked 52 in the Sunday Times list, up from 73 last year. In the past year, he and his wife Harriet Heyman have donated £18.2 million to University College San Francisco to fund biomedical research PhD programmes. In 2012, Moritz stepped back from daily duties at Sequoia after being diagnosed with an incurable illness.

He continues, however, to invest in new tech companies, such as payment platform providers Stripe and Klarna, as well as Skyscanner. Major tech brands he invested early in include Google, LinkedIn, Paypal, Yahoo, Zappos, Plaxo and Flextronics.

Digicel Group

Richer than Moritz and the wealthiest tech billionaire was Denis O'Brien, who owns mobile telco operator Digicel Group and its associated mobile phone companies.

Worth £3.85 million, Ireland's richest man ranks 22 in the Sunday Times list, falling from 20 in 2013. The source of his wealth was Esat Digifone, which won Ireland's second mobile phone licence. He sold the operation to BT for £175 million. Today, his Bermuda-based business Digicel Group is the largest mobile telco in the Caribbean, and operates in 31 countries.

He also owns a 29.9 percent stake in Independent News & Media, eight radio stations in the UK and 19 in Latvia, Bulgaria and Jordan.

Phones 4U

John Caudwell, 61, also made his fortunes from the mobile industry, which he joined in 1987. He sold most of his Caudwell Group - which owns high street mobile phone retailer Phones 4U - in 2006, earning £1.24 billion. Prior to this, he sold his Singlepoint customer billing business to Vodafone for £405 million.

His value has remained at £1.5 billion since last year, but Caudwell has fallen in rank from 50 to 57 this year.

Carphone Warehouse and TalkTalk

Bringing up the tech billionaire list's rear is Sir Charles Dunstone, aged 49, who has a combined stake in mobile phone retailer Carphone Warehouse and telco provider TalkTalk worth £1.39 billion.

Dunstone is ranked 62 with his total value of £1.49 billion in the Sunday Times list. He has climbed from 81, his rank in 2013 when he had £1.08 billion.