Wall Street bonuses are expected to decline for the first time since 2011, according to a study by compensation consulting firm Johnson Associates Inc.

Year-end compensation will be lower by 5 percent to 10 percent broadly throughout the financial services industry, the report said on Monday, with fixed-income traders experiencing an even larger drop as bond trading revenue continues to be weak.

Payouts to investment bankers who advise companies on mergers could rise 15 percent to 20 percent as the global market for dealmaking remains strong.

Compensation for debt traders, meanwhile, could fall as much as 20 percent from a year ago as doubts about Federal Reserve interest rate policy and China's economic slowdown have negatively affected banks' bottom lines.

Morgan Stanley said last quarter that bond trading revenue had fallen 42 percent, while Goldman Sachs Group Inc reported a 33 percent decline.

Investment bankers who help companies underwrite initial public offerings may experience a pay decline of 5 percent to 15 percent. Many companies have decided to stay private for longer amid choppy markets.

Banks are setting aside less money for pay. Goldman said it had earmarked 16 percent less money for compensation in the third quarter than it had for the same period last year. JPMorgan Chase & Co also said it had set aside 13 percent less money for compensation.