Goldman Sachs Group Inc.’s chief credit strategist Lotfi Karoui is leaving the Wall Street bank after 18 years, according to an internal memo reviewed by Bloomberg.

Karoui, who was also the head of credit, mortgages and structured products research, was named chief credit strategist in 2017 and was among 95 executives promoted to partnership in November.

His departure comes as Goldman Sachs’s chief US equity strategist, David Kostin, is set to retire from the bank at the end of the year, Bloomberg reported last month.

Karoui joined Goldman in 2007 as an associate in credit strategy research. He became a managing director in 2015, according to the memo.

A representative for Goldman confirmed his departure but declined to comment further. Karoui didn’t respond to requests for comment.

Prior to joining Goldman, Karoui taught undergraduate and graduate level courses in finance and operations research at McGill University and HEC Montreal, where he earned his PhD in financial economics and a masters in financial engineering respectively, according to his profile on Arab Bankers Association of North America website. He is chairman of that organization. Karoui was born and raised in Tunisia, according to ABANA.

In one of his latest notes, the strategist downgraded European investment-grade bonds from banks to underweight from neutral, saying sovereign fiscal risk — most notably in France — poses more downside risk to the banking sector.

Goldman chief credit strategist Karoui exits after 18 years