Top bank executives may see their bonuses cut by as much as 30 percent this year compared with 2010, according to a projection from a compensation consulting firm released on Friday.

Johnson Associates, which works with Wall Street banks and commercial banks, said it expects most areas of the finance industry to face bonus declines, with fixed-income employees taking the biggest hit.

The consulting firm expects senior firm managers to face a zero to 30 percent drop in bonuses from 2010, with fixed-income traders, bankers and salespeople facing a 20 percent to 30 percent decline. It predicts employees in equities sales and trading to face a less harsh decline of zero to 15 percent.

On the bright side, Johnson Associates said it expects investment bankers to receive a 5 to 10 percent boost in bonuses, due to an increase in mergers and acquisitions activity, as well as growth in debt and equity offerings.

Johnson Associates said it expects mixed results for retail and commercial banking employees, with bonuses moving in a range of negative to positive 5 percent.

The report comes in the wake of wild gyrations in the stock and bond markets this week that have fueled concerns about the health of the global financial industry.

Several financial firms, including Goldman Sachs Group Inc , Morgan Stanley , Barclays PLC and Credit Suisse Group AG , had already announced plans to lay off thousands of workers before the recent market rout, as part of broader plans to cut costs and boost profits.

Many Wall Street banks reported disappointing second-quarter results, due to a slowdown in trading revenues from fixed income, currency and commodities products. Meanwhile, commercial banks faced weak loan growth and others, like Bank of America Corp , continued to face losses from their mortgage divisions.

Johnson Associates included a caveat that its bonus predictions are based on the assumption that turbulent market conditions don't lead to 2008 type meltdown.

(Reporting by Lauren Tara LaCapra, editing by Knut Engelmann)