The billionaire founder of Bridgewater Associates believes that the ability of central banks to reverse an economic downturn is waning as the global economy enters “the late stages of the long-term debt cycle.” This according to a recent Bloomberg article.

The article reports that in a recent essay posted on LinkedIn, Dalio wrote: “Interest rates get so low that lowering them enough to stimulate growth doesn’t work well.” Increasing the money supply and buying financial assets don’t work either, he added, as they don’t produce sufficient credit in the real economy and “create large budget deficits and then their monetization.”

According to Dalio, the forces at work are similar to those in effect from 1935 to 1945. “There is a lot to be learned by understanding the mechanics of what happened then,” he wrote.