It's quite possible that 2015 could be the first year in a while where global diversification rewards investors, Schwab's chief investment strategist Liz Ann Sonders told attendees at a Women in ETFs breakfast in Fort Lauderdale.

U.S. markets have now significantly outperformed most other markets for more than three years, she noted. For financial advisors practicing global diversification with client portfolios, the fact that this strategy has underperformed domestic-only equities has become a conversation point with some clients.

Sonders was speaking on a panel at the breakfast, part of the eighth annual Inside ETFs conference, with Mary Ann Bartels, managing director and CIO of portfolio solutions at Banc of America Merrill Lynch. The session was moderated by F-Squared Capital President Sharon French.

Both Bartels and Sonders said they wouldn't be surprised to see an uptick in volatility. Bartels commented that all the e-mails she get these days from Europe ask what U.S. stocks European investors should buy for yield. Many Merrill analysts are concerned about Europe and Japan.

"We've never seen this type of central bank policy before," she said, adding Europe is seeing a lot of growth in negative yielding assets. Indeed, Swiss government bonds are the most glaring example.

Sonders and Bartels seemed to differ on when the U.S. Federal Reserve Board might raise interest rates. Given the levels where European government bonds are trading, Bartels thought the Fed might find it challenging to raise rates this year.

Sonders said "it's too soon to know" whether they would raise rates in June or September. "Prices have been kept artificially low for so long the adjustment process could be painful," she warned.

She wouldn't be surprised if the financial markets entered a period similar to the late 1990s, when a number of financial crises started to pop up in areas like commodities and emerging markets, all within a secular bull market.

Like the late 1990s, Sonders noted that consumer sentiment is improving. "This might be the year Main Street feels better than Wall Street."