Following a strong fourth quarter from its wealth management unit, Morgan Stanley plans to spend more than $500m over the next 18 months to improve computer systems for the 16,780 financial advisers and support staff who work in its brokerage joint venture with Citigroup.

In a memorandum to all Morgan Stanley Wealth Management employees on Wednesday reviewed by Dow Jones Newswires, brokerage president Gregory Fleming said the firm plans to make technology investments "above and beyond basic running costs" in order to "ensure and accelerate the improvement of our platform's stability and functionality."