Wall Street banks have suffered a major slowdown in corporate dealmaking activity as a result of volatile global financial markets.The bank's chief executive David Solomon sent a year-end voice memo to staff warning of a headcount reduction in the first half of January, two separate sources said.The bank restarted its annual performance review process and staff cuts in September after pausing for two years during the pandemic.Global banks, including Morgan Stanley (MS.N) and Citigroup Inc (C.N), have reduced their workforces in recent months as a dealmaking boom on Wall Street fizzled out due to high interest rates, tensions between the United States and China, the war between Russia and Ukraine, and soaring inflation.Banks had executed $517 billion worth of equity capital markets (ECM) transactions by late December 2022, the lowest level since the early 2000s and a 66% drop from 2021's bonanza, according to Dealogic data."