#MarketRebound

markets," Schassler said.

Investing icons of the recent past, from Warren Buffett to Jack Bogle of Vanguard Group, broadcast a message that focusing on U.S. stocks over the long-term is the best bet. Bogle, in particular, often said the S&P 500's multi-national corporate makeup delivers plenty of overseas revenue itself. But even Buffett has been lightening up on some big U.S. market positions, while adding to more of his more recent bets on Japan.

"We're not anti-U.S., but just saying if you are predominantly invested in the U.S., you probably want to invest outside as well," Schassler said.