E. F. Hutton & Co. is ending municipal bond underwriting and trading operations in five regional offices, becoming the latest Wall Street firm to pull back from the business. The New York-based company said the move, which will mean the firing of about 40 employees, was a response to changing market conditions that have reduced profitability in the municipal bond business. The firm will end municipal bond underwriting and trading activities in its regional offices in Atlanta, Denver, Kansas City, Philadelphia and Seattle. Hutton will continue to engage in public finance and investment banking services from those offices. Municipal bond underwriting and trading will be consolidated at offices in New York, Los Angeles, Houston, Chicago, Boston and Boca Raton, Fla.