The pledge is among the largest philanthropic gifts ever — outpacing the historic contributions of industrialists like John D. Rockefeller and Andrew Carnegie when adjusted for inflation.

Bill Gates marked the 25th anniversary of the foundation by announcing it would wind down by the end of 2045 in order to maintain spending levels.

Microsoft co-founder Bill Gates will dramatically speed up his plans to give away most of his wealth, saying he will reduce his estimated $108 billion net worth by 99 percent over 20 years and prepare his eponymous foundation to stop operating by the end of 2045.