Robert Day, the founder and chief executive of US fund management firm TCW, is sitting on €111m ($110m) of shares in Société Générale, after the French bank bought control of TCW last year.

The publicity-shy Day is set to receive another €41m over the next four years as SocGen buys another 19% of TCW in four tranches, in a deal that values his overall holding at €217m. If TCW meets its growth forecasts, Day's stake will be worth well over €300m. As recently as May, the year-high for SG shares, his entire stake was valued at nearly €320m.