Read IBM CEO's letter to investors warning about its poor results: 'This quarter we faltered'

IBM CEO Arvind Krishna warned investors that the company's second-quarter results fell short of expectations. Mandel NGAN / AFP via Getty Images IBM CEO Arvind Krishna sent a warning letter to investors about its below-par Q2 results. Customers pulled back from spending on IBM products to prioritize buying memory and chips, he said. Read Krishna's full letter to IBM shareholders below. IBM shares tanked on Tuesday after the tech giant released preliminary second-quarter results that fell…