On the plus side, though, some risk is already priced in. Russian and Kazakh bonds for instance trade as though they were several notches into junk.
Also ratings don't much matter to dedicated emerging market funds and increasingly to some institutional investors who may base allocations on asset managers' analysis, rather than solely on ratings.
Wayne Bowers, EMEA and Asia chief investment officer at Northern Trust, says many big investors have built in the flexibility to hold different kinds of emerging assets in recent years. Also, he notes, while some countries' outlook has darkened, others will benefit from reforms and cheaper oil.
"People usually understand EM is not a low-risk asset class." Bowers said. "You will find the return profile of the broader indexes can offset the negatives... It's not just focused on countries that are fragile but also those that benefit from falling oil prices."