Warren Buffett donated on Friday another $6 billion of Berkshire Hathaway stock to the Gates Foundation and four family charities, his biggest annual donation since he began giving away his fortune nearly two decades ago.

Warren Buffett has never been one to chase headlines. For most of his career, the 93-year-old billionaire investor has preferred to let his actions—and his annual shareholder letters —do the talking. But even Warren Buffett can’t give away $6 billion in a single day without people noticing.

Buffet, 94, is donating 9.43 million shares to the Gates Foundation; 943,384 shares to the Susan Thompson Buffett Foundation; and 660,366 shares to each of three charities led respectively by his children Howard, Susie, and Peter: the Howard G. Buffett Foundation, Sherwood Foundation and NoVo Foundation. The donations will be delivered on Monday.