Dutch-Belgian financial services group Fortis said its profit halved in the fourth quarter after a 1.5 billion euro ($2.3 billion) subprime-related writedown.

Net profit, which also included gains from Fortis's 2007 acquisition of ABN Amro's Dutch business and divestment of a joint venture, fell by a worse-than-expected 48 percent to 414 million euros from a year earlier, it said on Friday.