Sullivan said JPMorgan's house view is that the greenback was already inflated to a 14-year trade-weighted high. "We don't have a lot of upside left to the dollar, which helps drive a positive view on emerging markets," he said.
EMs are sensitive to U.S. interest rate changes because many governments and companies borrow in dollars. An increase in rates can lead to a stronger dollar and to greater capital outflows from EMs, as investors seek returns.
On global growth, Sullivan said he saw a "very strong" rebound in global manufacturing. This is a positive for EMs, particularly those heavily involved in manufacturing, he said.
Fed Chair Janet Yellen told Congress on Tuesday that waiting too long to raise interest rates would be "unwise" as economic growth continues and inflation rises. When the Fed last hiked rates at its December 2016 meeting, Federal Open Market Committee members indicated three more increases were likely in 2017, though many market watchers realistically now expect just two moves.
JPMorgan expects the first rate hike for the year to come at the June meeting.