Moritz, who topped Forbes' Midas List in 2006, has investments in Yahoo!, PayPal, eBay, Apple and YouTube, and has an estimated fortune of £558m. He is chiefly a venture capitalist at Sequoia Capital, where he focuses on software development.
Duncan Cameron and Simon Nixon, chief technology officer and chief executive officer at price comparison website Moneysupermarket.com are tied at number six in the list, dropping 27 places from last year, with a wealth totalling £480m each.
Paul Sykes, owner of price comparison website , is ranked at number five with £520m, Michael and Xochi Birch, co-founders of , are at number 15 with £150m, followed by Nick Denton, founder and owner of and at number 16, who has an estimated wealth of £140m.
The Sunday Times online rich list is topped by Peter Cruddas, chairman and chief executive of CMC Markets, who has dropped four places, with a fortune of £1bn. Cruddas is also the largest individual donor for the Prince's Trust.
However, the top 20 features seven entries from people who have made their millions in the online gaming industry, with Party Gaming, Betfair and Bet365 featuring heavily.
Anurag Dikshit, co-founder of PartyPoker.com's parent business PartyGaming is ranked number two on the list, with a fortune of £920m. He is joined in the Sunday Times list by PartyGaming co-founders Russell De Leon and Ruth Parasol, who are at number three with £856m.
Peter and Denise Coates, co-founders of Bet365, which was acquired by Coral for around £40m, are at number 11 with £200m. Andrew Black and Ed Wray, co-founders of Betfair are joint 12th with £190m, with Richard Koch, investor and director at Betfair at number 17 with £130m.