The iShares MSCI Emerging Markets ETF, which tracks the group, surged more than 18 percent in a five-month span from July 2017 to January 2018, but has given back a big chunk of those gains in 2018 and is down about 10.3 percent year to date. By comparison, the has risen nearly 1 percent during a volatile 2018, while the Vanguard FTSE All-World ex-US Index Fund , which tracks global equities minus the U.S., is off more than 6.5 percent this year.

The most recent exodus, which includes exchange-traded and mutual funds, comes amid worries that the much-touted synchronized global expansion is running out of gas, as well as some unwinding of what had been a hugely successful trade in emerging market stocks.

Global equity funds have seen outflows of $12.4 billion in June, a level not seen since October 2008, according to market research firm TrimTabs. Lehman Brothers collapsed in September of that year, triggering the worst economic downturn since the Great Depression and helping fuel a bear market that would see major indexes lose more than 60 percent of their value.

Investor money is hemorrhaging out of global stock funds at a pace not seen since just after the financial crisis exploded.

As the emerging market and non-U.S. trade has unwound and fears have intensified over a trade war, investors have fled global stocks and returned to the U.S., where funds have seen $6.3 billion in inflows. The iShares emerging market ETF has seen $5.4 billion in outflows in June, the most of any fund, according to ETF.com.

"U.S. dollar strength and persistent underperformance seem to be driving fund investors away from non-U.S. equities," TrimTabs said in a note.

Interestingly, one of the regions suffering the lowest level of investor fear is China, where funds have seen a net inflow of $150 million even though the nation's main stock index has plunged into a bear market, defined as 20 percent below its most recent high.

For investors, then, the main question may be whether the outflows elsewhere are signaling something more ominous or are merely setting up another buying opportunity as valuations get cheaper.

"Cumulative flows for the year [across asset classes] are still up [thanks] to strong inflows in January. Russia and [South] Africa are now driving the outflows, as the most crowded markets at the eve of recent weakness," Gabriele Foa, cross asset strategist for emerging markets at Bank of America Merrill Lynch, said in a note. "Selected opportunities are emerging thanks to weak levels."

In fact, if the trend holds up through the end of June, it will make the first time global equities have seen net outflows since November 2016, according to TrimTabs.

Investors, however, remain bullish on Latin America, which has seen $30 million in inflows to ETFs in June even though the funds have lost 10 percent in June and more than 25 percent since May.