Two co-heads of Goldman Sachs' securities division - Isabelle Ealet and Pablo Salame - will retire next month after 20-year stints at the Wall Street bank, according to an internal memo seen by Reuters.

The departures leave Ashok Vardhan as the unit's sole chief. A source familiar with the matter said Goldman has no immediate plans to appoint new division heads.

Ealet joined the bank as a commodities trader in 1991. Salame joined in 1996 and became co-head of the securities group in 2008.

Ealet and Salame were occasionally touted as potential CEO candidates for the bank. But after a long-running succession race resulted in Chief Executive Officer Lloyd Blankfein highlighting David Solomon as his choice, their future appeared less certain.

Goldman has been overhauling its trading business, which includes equities trading and fixed income, after one of its worst years on record.

Blankfein as well as other top executives have told investors that the bank is looking to increase trading revenue by leveraging the relationships investment bankers already have with corporate clients.

Goldman shares (GS) were up 1 percent at $245.50.