Warren Buffett offered a full-throated defence of share buybacks in his annual letter to Berkshire Hathaway shareholders on Saturday, saying stock purchases by Berkshire and the dozens of publicly traded companies it owns are a boon to investors.

The comments from the 92-year-old investor came in the shortest annual letter he has published in decades and accompanied results that showed Berkshire suffered a $22.8bn loss last year, driven by a slide in the value of its stock portfolio.

Buffett’s defence comes weeks after a new tax on stock buybacks went into effect in the US. The tax was one of the few revenue raising measures that found unanimous support among Democrats in the Senate when they passed the Inflation Reduction Act, president Joe Biden’s sweeping climate and tax law.