Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Stocks returned to their downward ways Wednesday, all but assuring a losing January for the S&P 500 for the first time since 2010. Yet even as concerns about emerging-market economies outweighed solid earnings results from many prominent companies, several stocks gained substantial ground today. Among them were Freescale Semiconductor (UNKNOWN:FSL.DL), Medivation (NASDAQ:MDVN), and Horizon Pharma (NASDAQ:HZNP), all of which rose by double-digit percentages today.

Semiconductor-chip manufacturing specialist Freescale Semiconductor rose 15% after the company reported encouraging earnings results yesterday afternoon. The company grew sales by 13%, beating expectations even though it posted a wider loss due to one-time items. Positive guidance on revenue during the current quarter also lifted shareholders' spirits, and analysts at Citi, Needham, and Pacific Crest Securities all made positive comments that supported the stock's gains.

Medivation gained 11% after the cancer-treatment-focused biopharmaceutical company got good news from its phase 3 trial of development drug Xtandi. The study demonstrated that prostate cancer patients showed significant delays in the progression of cancer among those taking the drug, potentially leading to a blockbuster result that could knock out existing therapies. If Medivation can win approval to expand its indicated uses to include treatment before chemotherapy takes place, the company could see much faster growth in the drug's revenue.

Horizon Pharma soared 18% as the specialty-pharma company continued its impressive share-price run after delivering preliminary results for the fourth quarter. Horizon cited reports from Source Healthcare Analytics that total prescriptions of its Duexis inflammation drug rose 13% while its Rayos delayed-release prednisone tablets climbed 18%. The company also said that its acquisition of arthritis combination-therapy Vimovo has gone well, with prescription growth pointing to potential future success. Horizon still isn't profitable, but solid results from its stable of drugs could change that in the near future.