IBM's Arvind Krishna tells investors missteps and delayed mega-deals drove a selloff that erased billions in market value

IBM released preliminary second-quarter results showing revenue fell well short of Wall Street expectations, weighed down by a slide in infrastructure sales. Revenue from the company's Z mainframes and related transaction-processing software missed forecasts by a wide margin. In a letter to investors, CEO Arvind Krishna said IBM "faltered," pointing to large deals that did not close on schedule and a temporary shift in customer capital spending toward scarce items such as memory and servers. The disappointment triggered a historic market reaction: IBM shares dropped 25% for the week, the steepest weekly decline in nearly four decades.