Confidence-shaking technology mishaps have been an almost daily occurrence at the nation’s stock exchanges in the new year.

The latest example came Wednesday night when the nation’s third-largest stock exchange operator, BATS Global Markets, alerted its customers that a programming mistake had caused about 435,000 trades to be executed at the wrong price over the last four years, costing traders $420,000.

A day earlier, the trading software used by the National Stock Exchange stopped functioning properly for nearly an hour, forcing other exchanges to divert trades around it. The New York Stock Exchange, the nation’s largest exchange, has had two similar, though shorter-lived, breakdowns since Christmas and two separate problems with its data reporting system. And traders were left in the dark on Jan. 3 after the reporting system for stocks listed on the Nasdaq exchange, the second-biggest exchange, broke down for nearly 15 minutes.

The stream of errors has occurred despite the spotlight on the exchanges since a programming mishap nearly derailed Facebook’s initial public offering on Nasdaq last May and BATS’s fumbling of its own I.P.O. two months earlier. At the end of 2012, a number of exchange executives said they were increasing efforts to reduce the problems. But market data expert Eric Hunsader said that the technology problems have become, if anything, more frequent in recent weeks.