The Brexit vote has created fear across global capital markets, creating a slew of buying opportunities, particularly in assets that were already cheap, said Chris Brightman, chief investment officer at Research Affiliates.

"If you look at Europe in particular, you now have the opportunity to buy very cheap equities with cheap currencies and the same is true in many emerging market countries," said Brightman.

Research Affiliates was a pioneer of fundamental indexing, an approach that uses fundamental measures of a firm's economic footprint, rather than market capitalization, in index construction.

Brightman is also positive on high yield bonds in the current low-yield environment. He said negative nominal yields in places like Japan are making so-called junk bonds more than worth considering.

"The high yield may only be offering you a fair spread, but a fair spread over a zero real yield is actually a fairly attractive opportunity. And today's environment gets you back near to the entry prices at year-end, which was a fabulous entry point for high yield," said Brightman.

On the flip side, Brightman said investors should avoid long-term Treasury bonds.

"I wouldn't necessarily tell an investor who holds a broadly diversified portfolio that they should be completely out of Treasuries, because long-term Treasuries are the most diversifying asset that you have," said Brightman. "When the world blows up, that's the one thing you can be confident will appreciate, and yet at today's yields I would have about the biggest underweight as you can tolerate to long term Treasuries."

Brightman is also less bullish on U.S. small cap stocks, calling them "a little pricey relative to their historical average valuation multiples relative to the rest of the market."

Finally, Brightman is not a fan of gold in a portfolio because "it just sits there without paying you anything."