Morgan Stanley (MS) - Get Report  said first-quarter profit fell 9% from a year earlier as revenue tumbled in the Wall Street firm's trading unit as well as from key investment-banking businesses like advising on mergers and underwriting stocks and bonds.

Net income declined to $2.43 billion, or $1.39 a share, the New York-based company said Wednesday in a press release. Excluding an unexpected tax benefit of 6 cents a share, the firm earned $1.33 a share, beating the average analyst estimate of $1.17 in a survey by the data provider FactSet. 

The shares rose 2.3% to $48.08 in premarket trading Wednesday. 

"We delivered solid earnings despite a slow start to the year following the turbulent markets in the fourth quarter," Morgan Stanley CEO James Gorman said in the press release. 

Trading revenue fell by 15% from a year earlier to $3.74 billion, driven by lower activity in stocks and derivatives, less lending to hedge funds and worse results in government bonds and forcing exchange, Morgan Stanley said.

Investment-banking fees fell by 24% to $1.15 billion, as the pace of corporate mergers slowed, fewer companies held initial public stock offerings and junk-bond sales slowed.  

The firm's juggernaut wealth-management division, including Morgan Stanley's network of 15,708 financial advisors and brokerage representatives, produced revenue of $4.39 billion, unchanged from the year-earlier level. Asset-management revenue decreased due to lower market levels at the start of the quarter, while transactional revenue increased, reflecting gains on investments owned in deferred-compensation plans.