Net Worth: $2.9 billion

LAST YEAR: $2.2 billion
CHANGE: 33%
AGE: 103
RESIDENCE: Hancock Park
SOURCE OF WEALTH: Insurance

Joseph continues to be ranked by Forbes as the oldest billionaire in the world and is one of two centenarians on this year’s Business Journal Wealthiest list. He served as a navigator on a B-17 bomber during World War II and started Mercury after working as a door-to-door life insurance salesman. The carrier Joseph was working for at the time balked at his idea of moving into auto insurance, so he struck out on his own, offering low-cost auto and home policies, launching Mercury in 1961. Last year, Mercury had 4,100 employees and wrote $4.27 billion in premiums. But, like many insurers, Mercury was reeling from sharp increases in both the number of claims due in part to climate change and the cost per claim; the result was that claims costs shot way up over premium revenue, depressing the stock price. But this year, Mercury brought claims costs down to less than premium written and returned to profitability. Over the last year, its share price has more than doubled, driving up the value of Joseph’s 35% stake by 121%. That, combined with modest growth in his massive dividend pool, pushed his net worth up 33%.

In office: Joseph was still putting in appearances at Mercury’s mid-Wilshire headquarters well into his 90s.

Real Estate: He has a home in nearby Hancock Park and another in Santa Barbara.

Charitable Giving: Joseph and wife Vicky have made philanthropic contributions to USC, Harvard University, Cal State Fullerton, Cedars-Sinai Medical Center and Good Samaritan Hospital.