Surely the rich guy isn't saving by stashing the money under his mattress.... Perhaps Krugman is simplifying for those of us who don't have degrees in economic

Surely the rich guy isn't saving by stashing the money under his mattress.... Perhaps Krugman is simplifying for those of us who don't have degrees in economics, but he's suggested multiple times that rich people who "save" their money somehow take that capital out of circulation.