Why GW Pharmaceuticals Stock Jumped 17.7% in September

GW Pharmaceuticals (NASDAQ: GWPH) stock jumped 17.7% in September, according to data from S&P Global Market Intelligence.

Most of this gain, however, was given back over the past week, as shares lost 12.5% in the first week of October. The U.K.-based biopharmaceutical company's stock has gained 33.1% over the one-year period through Oct. 5.