After five years of shrinking sales, IBM finally turned the corner in 2018, reporting modest revenue growth in January. Since then, Big Blue has posted a bump in sales each period, much of it coming from the old-school mainframe computing business. It’s a good sign for Rometty, but Wall Street is looking for clearer signals that IBM’s newer businesses, like its cloud-computing and data-crunching units, will lift the company for years to come. IBM’s stock is relatively flat over the past year, vs. a 16% rise for the S&P 500 index.