The industry heavyweight will continue to serve as chief investment officer following the change, overseeing long-term strategic convictions.
Older was appointed as a co-fund manager of the flexible mixed asset fund in September 2018 to manage the equity part, while Ouahba has been overseeing the fixed income segment alongside Carmignac.
Commenting on his decision, Edouard Carmignac said: '30 years after the creation of Carmignac, I am pleased to entrust Rose and David with the management of Carmignac Patrimoine.
'I am also proud to have been able to set up such an experienced, talented and high-calibre investment team to support them in managing our flagship fund.'
Since the launch of the fund in November 1989, the Patrimoine fund has returned 659.2% in euro terms, while the Citywire-assigned index LCI MSCI AC World NR USD/FTSE WGBI TR EUR (50:50) rose by 96.12% over the same timeframe.