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What's happening: Shares of Teradata Corporation (NYSE:TDC) fell 10% Thursday after the company announced mixed fourth-quarter results and offered lower-than-expected 2015 guidance.

Quarterly revenue fell 1% year over year (but increased 3% on a constant currency basis) to $761 million, which translated to a 2.7% decline in adjusted net income to $140 million. On a per-share basis, net income increased by $0.03 to $0.91 thanks to stock repurchases during the year. Analysts, on average, were looking for slightly lower earnings of $0.90 per share on higher sales of $778.9 million.

Why it's happening: "Teradata's fourth-quarter and full-year financial results were roughly in line with what we were expecting," said Teradata CEO Mike Koehler. "However, we are not satisfied with these results."

Going forward, Koehler says Teradata is making significant increases to investments in its product portfolio in 2015, including Big Data Analytics, Marketing Applications, Teradata Cloud, and "in demand creation to go broader in the market." As such, it expects full-year revenue to be flat to down 2% from 2014, resulting in a range of roughly $2.68 billion to $2.73 billion, which should result in adjusted earnings per share of $2.50 to $2.70. Wall Street was modeling 2015 revenue and earnings of $2.83 billion and $2.99 per share, respectively.