The skinny on the fat wallets of L.A.’s 50 wealthiest.

Alfred Mann

NET WORTH: $1.5 billion -15%

LAST YEAR: $1.78 billion

AGE: 85 RESIDENCE: Beverly Hills

SOURCE OF WEALTH: Aerospace, medical devices

THE MONEY: Net worth of L.A.’s best-known entrepreneur tumbled after his MannKind Corp. hit by continued regulatory delays in approving inhalable insulin for diabetics. Fortune based on building and selling several medical device companies.

BUZZ: Stock market roller-coaster continues for namesake drug developer MannKind. U.S. regulators in January delayed approval of Afrezza inhaler until more studies performed. Value of Mann’s 39 percent stake down 35 percent. He and his fourth wife, Claude, split time between Mulholland Drive mansion and Las Vegas home, where wired home offices and private jets enable octogenarian to put in an 80-hour workweek when necessary. Founded 16 companies and still controls or has significant stakes in multiple startups. Largest payday was $3.7 billion when he sold insulin pump developer MiniMed to Medtronic in 2001. More recently, sold Valencia hearing implant maker Advanced Bionics in late 2009. Oregon native moved to L.A. after World War II and caught entrepreneurial bug after founding two aerospace companies in 1950s. Continues to support eponymous medical research foundation, and three incubators that help professors at USC, Purdue University and Israel Institute of Technology commercialize bioengineering research. Early signers to Bill Gates and Warren Buffett Giving Pledge, donating half of fortune to charity. In March, the couple gave $4 million to the Walter W. Naumburg Foundation, a Manhattan School of Music charity that sponsors competitions for young classical musicians.