Warren Buffett’s annual donation of shares to the Bill and Melinda Gates Foundation this year was valued at $1.6bn (£1.1bn), 28% higher than last year’s total, despite gifting fewer shares.

In 2006 Buffett, CEO of Berkshire Hathaway, pledged to give annually to the Foundation throughout his lifetime. He earmarked 10 million of his Class B shares in the company for contributions, representing almost all of his personal fortune, with the number of shares gifted reducing by 5% each year. Following a 50-for-one stock split in January 2010, the number of shares pledged equates to 500 million.

The shares are up almost 35% in value over the past 12 months, and bring his donations to the Foundation over the past five years to nearly $8bn – the original value of all pledged shares in 2006.

Buffett and Gates are now campaigning for other philanthropists to give at least 50% of their net worth to good causes in The Giving Pledge, reported on in last week’s Philanthropy UK Bulletin.