Pioneer Investments and Santander Asset Management are on the verge of agreeing their long-awaited merger with a deal expected as early as next week, according to people familiar with the matter.

Giordano Lombardo, confirmed as interim chief executive of Pioneer following the departure of Sandro Pierri in January, is expected to become chief investment officer of the newly-merged entity, leaving Juan Alcaraz, head of Santander Asset Management, in the chief executive role, the people said.