In 2006, he sold 5,300,000 sq ft (490,000 m) of his real estate holdings for roughly $1.1 billion.
Arrillaga is known for his support of Stanford University. The alumni center, the Frances C. Arrillaga Building, is named in memory of his first wife, and other athletic facilities carry his surname. In May 2006, Arrillaga gave $100 million to Stanford.