Net Worth: $2.6 billion

LAST YEAR: $2.4 billion
CHANGE: 8.30%
AGE: 89
RESIDENCE: Bel Air
SOURCE OF WEALTH: Initially petroleum; currently investments

Born in Lebanon, Irani came to Los Angeles at age 18 with $75 in his pocket to study chemistry at USC. He made his initial fortune as longtime chief executive and major shareholder of oil giant Occidental Petroleum Corp. During his 21-year tenure as chief executive, Irani used his overseas connections to expand the company’s reach and presided over a 15-fold growth in market cap to more than $80 billion. Since leaving Occidental in 2011, he set up a family office in Westwood and, under the Cedar Tree Capital banner, has worked to grow his portfolio. His holdings include hedge funds, medical office buildings, apartment buildings and public storage companies. He has also made private equity investments in a wide range of companies, including cybersecurity and robotics firms. Over the past year, his portfolio has seen steady gains.

Education: Has remained loyal to USC; he taught classes there into his 80s and is a “life trustee.”

Charitable Giving: Irani is a major supporter of the House of Lebanon the cultural heritage of his native country. He also has given extensively to both USC and UCLA.