Sovereign debt markets are likely once again to become a major source of concern for European Central Bank officials in the months to come.

As governing council members laid out plans this week to accelerate the end of net asset purchases, Italian, Spanish and Greek sovereign bond yields climbed rapidly. Some investors see in this trend a harbinger of greater stress, in an environment that has become used to constant ECB interventions.

“There are huge risks,” says James Athey, investment