THE MONEY: Memory-disk makers had banner year in 2013 and Tu’s Kingston Technology shared in growth. Thanks to recovery period after supply glut in 2012, revenue surged to $5.4 billion in 2013 as prices rose for core personal computing product.

BUZZ: Kingston rebounded from slow sales in 2012, catapulting Tu in this year’s rankings. He and David Sun sold Kingston in 1996 for $1.5 billion, bought it back three years later for $450 million. Fountain Valley company’s 7 percent revenue jump came mostly from sales of its DRAM modules, used in desktop and laptop computers. Modules sold for about $18 on average last year, 33 percent increase over 2012 as costs largely held steady. Twenty-six-year-old company controls nearly half of global DRAM market. Kingston launched portable media reader for tablets and smartphones that lets three users share data simultaneously. Lives in small Palos Verdes community of Rolling Hills, spends most of his time in Orange County. Drummer, he and band JT and California Dreamin’ regulars at charity events, including annual UC Irvine Health School of Medicine Gala, to which Tu has made sizable donations.

NET WORTH:

$4.5 billion s88%

LAST YEAR: $2.4 billion

AGE: 72

RESIDENCE: Rolling Hills

SOURCE OF WEALTH: Computer technology