World Bank chief economist Pinelopi Koujianou Goldberg on Wednesday announced she will be leaving the institution, according to a letter sent to colleagues and obtained by AFP.

Calling it a "difficult decision," Goldberg wrote that she will step down from her post on March 1 to return to teaching at Yale University.

"This has been a rewarding experience, to work with you on the issues that we care deeply about and ensure that development economics serves to create opportunities for the poor," she told her colleagues in the letter.

In a separate letter, World Bank President David Malpass said research director Aart Kraay would take over for Goldberg until a new permanent chief economist is hired.

"I appreciated Penny's passion for building the institution's connection to state-of-the-art academic research and her commitment to drawing young talented economists to the bank, an effort that will continue beyond her departure," Malpass wrote.