The stock market enjoyed a quiet day on Tuesday that sent major market benchmarks to modestly higher levels. Most indexes finished with gains of 0.2% or less, as investors seemed torn between the positive momentum that the market has produced lately and the uncertainties involved with geopolitical and macroeconomic trends right now. Yet even though many portions of the market held up well, some stocks suffered fairly significant declines, and NVIDIA (NASDAQ:NVDA), Corvus Pharmaceuticals (NASDAQ:CRVS), and J.C. Penney (OTC:JCPN.Q) were among the worst performers on the day. Below, we'll look more closely at these stocks to tell you why they did so poorly.

NVIDIA deals with a downgrade

Shares of NVIDIA dropped 7% after the chipmaker received an analyst downgrade. Pacific Crest reduced its rating on the graphics-chip specialist from sector weight to underweight, citing an imminent shift away from desktop-based graphics processing units toward the mobile device market. NVIDIA benefited greatly from accelerating innovation in the graphics space in 2016, including the rise of virtual reality, and solid demand for data-center applications also powered the stock higher. Yet so far, 2017 doesn't appear to be carrying that momentum forward, and some fear that tough comparisons could disappoint growth-hungry shareholders. With attention turning back to the iPhone and other mobile releases, NVIDIA might see a pause in its upward track until the pendulum swings back in its direction in the future.

An NVIDIA chip.

Image source: NVIDIA.

Corvus falls after revealing trial results

Corvus Pharmaceuticals stock lost nearly half of its value in the wake of the company's release of interim results from an ongoing phase 1/1b study of its CPI-444 immuno-oncology therapy. The company said that treatment with CPI-444 both as a single agent and in combination with Genentech's atezolizumab was well-tolerated and resulted in anti-tumor activity in patients suffering from certain advanced solid tumors. Among the specific types of cancer covered under the study were breast cancer, non-small cell lung cancer, melanoma, and renal cell cancer. Yet investors seemed to want something more, and the stock gave back all of the extensive gains it had earned over the past month and then some. The Corvus experience shows how volatile biopharmaceutical investments can be, especially when clinical innovations are being considered.

J.C. Penney suffers from the retail blues

Finally, shares of J.C. Penney finished down 7%. The retail sector generally had a bad day on Tuesday, and analysts issued downgrades to various retailers in the wake of poor sales results and unappetizing prospects for the future. J.C. Penney in particular has suffered greatly in the recent past; its latest move came last month when it announced another wave of store closings in an effort to focus on its most promising markets. Yet despite efforts to broaden demand by offering appliances and other nontraditional items to its shoppers, J.C. Penney still hasn't convinced some investors that it can continue to compete in an increasingly difficult environment. With the shift toward online retail specialists still staying strong, J.C. Penney will have to work even harder to sustain and build its business going forward.

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