William Robert Berkley, who founded WR Berkley Corporation in 1967, has died aged 80.

Mr Berkley established the insurer six decades ago with $US2500 while he was studying at Harvard. He was CEO until 2015.

The business, which listed on the New York Stock Exchange in 1974, is now valued at almost $US6 billion ($8.51 billion). It operates in more than 60 countries and has annual revenue of more than $US14 billion ($19.88 billion).

Mr Berkley’s son, W Robert Berkley Jr, who is the Connecticut-based insurer’s president and CEO, has taken over as chairman.

“His influence on us, our company, and the broader industry and the countless lives he touched and enhanced is immeasurable,” Mr Berkley Jr said.

“An extraordinary leader and entrepreneur, whose vision and values shaped the company. His vision, discipline and unwavering commitment to an entrepreneurial culture focused on underwriting excellence and long-term results shaped the company’s success and leaves an enduring imprint.”

The insurer remains committed to “carrying forward his values, culture and long-term perspective”, Mr Berkley Jr said.

Mr Berkley, who died yesterday (US time), supported educational institutions, hospitals, research institutions and community-based programs, and his son says this philanthropy will “endure for generations”.

Howden Re’s Sydney-based head of treaty for Australia and New Zealand Richard Pike said on LinkedIn he met Mr Berkley a number of times while working for the US business for a decade.

“He was a visionary and an inspiration, and a genuinely nice human being. Sad day for the industry and for the Berkley family,” Mr Pike said.