Portfolio flows to emerging markets slowed sharply in August after months of robust investment, in what may be an early sign of a weaker appetite for risk, according to the Institute of International Finance.

Emerging markets received an estimated $9 billion in August, down from an average of $38 billion in May, June and July, data from the IIF, a Washington-based industry group representing financial companies worldwide, showed Wednesday.

“The usual seasonal lull surely contributed to the weakness,” IIF chief economist Charles Collyns said in a statement. “The sharp slowdown in portfolio flows in August could also mark the beginning of a period of greater caution among global investors.”

Emerging Europe and Africa led the slowdown, the IIF data showed. Both equity and bond issuance slowed in August, the group said in a statement, with bond sales dropping to $22 billion, half the level in the same month last year.

The Federal Reserve’s eventual exit from easy monetary policy could pose a risk to flows going forward, IIF economist Robin Koepke said in an interview, though “overall, we have a relatively favorable outlook for capital flows.”

The institute, which has almost 500 members, including investment banks and other financial industry companies from around the world, is releasing a new regional estimate drawing on bond issuance, country-level portfolio flows and other data. Wednesday’s release is the first in the series.