Hedge-fund manager Carl Icahn says he is “very cautious” on U.S. stocks, which “could easily have a big drop” from their new record highs. Ben Inker, a director at asset manager GMO, forecasts that overall, U.S. stocks will suffer losses of 2% annually, counting dividends and inflation, through 2020. Yet billionaire investor extraordinaire Warren Buffett says the U.S. stock market is valued “in a zone of reasonableness.”