Goldman Sachs Group Inc. Chief Executive Officer Lloyd C. Blankfein, grappling with a market slump that is putting trading earnings under pressure, said “sometimes cycles can last a very long time.”

Still, history shows that New York-based Goldman Sachs shouldn’t go “overboard” in reacting to downturns, Blankfein, 58, said today at the Bank of America Merrill Lynch 2012 Banking and Financial Services Conference in New York. Wall Street has made past mistakes by cutting too many employees at the bottom of cycles and over-hiring at the top, he said.

It’s Blankfein’s seventh straight appearance at the annual event sponsored by Charlotte, North Carolina-based Bank of America Corp.