OMAHA, Neb. --Warren Buffett says the U.S. economy appears weaker than he thought it would be as recently as last fall, but that doesn't change his optimistic long-term view of the country's prospects.
Buffett appeared on CNBC Monday after releasing his annual letter to Berkshire Hathaway shareholders over the weekend.
Buffett says the collapse in oil prices will be good overall for the American economy because consumers will have more money to spend.
But he says the negative effects of falling crude prices hit the oil industry immediately in terms of lost jobs and reduced company values. Buffett says the benefit to Americans trickles in slowly every time they fill up their gas tanks.
Buffett's letter, which reviews the operations of the conglomerate over the previous year, is one of the most widely read business reports.
In it, the billionaire investor criticized the negativity of the presidential race, saying children born in the U.S. today are the "luckiest" in history.
"For 240 years it's been a terrible mistake to bet against America, and now is no time to start," wrote Buffett, who has endorsed Hillary Clinton for president. "America's golden goose of commerce and innovation will continue to lay more and larger eggs."
Buffett signaled concern over how the nation's wealth is distributed, saying workers are often hurt by innovation and increased efficiency.
The cost of price of prosperity for most Americans "should not be penury for the unfortunate," he wrote.
The letter to shareholders came along with the release of fourth-quarter and annual results for, Berkshire Hathaway, which tallied earnings of $24.08 billion in 2015, up from $19.87 billion in 2014, while annual revenue increased by $16 billion, to $210.8 billion.
Buffett also said he can't predict how having interest rates negative for a prolonged period will affect the economy because it has never happened before.
The billionaire from Omaha said on CNBC Monday that Berkshire Hathaway's insurance units in Europe will lose money on the cash they have to keep in banks.
He joked that Berkshire would be better off stashing cash in a giant mattress instead of banks if only he could find a trustworthy person to sleep on top of a billion euros.
Buffett says he understands why regulators cut interest rates to help Europe recover, but there's no way to know how that will affect business.