Image: Advanced Micro Devices.

The stock market took a break Monday, trading in a relatively narrow range and consolidating the gains that it has posted in the past several weeks. Minor concerns sent the major market benchmarks down modestly during the early part of the day, but investors slowly but surely bid up stocks enough to allow the Dow to finish up from Friday's close. The S&P 500 limited its losses to just over a tenth of a percentage point. Yet even with the lack of excitement from the overall market, several stocks posted sharp gains, including Starwood Hotels & Resorts (NYSE: HOT), Advanced Micro Devices (AMD -5.44%), and GW Pharmaceuticals (GWPH).

Starwood Hotels & Resorts finished the day up 8% after the hotel operator saw a new player come into the mix in its bid to sell itself. China's Anbang Insurance Group made a $12.8 billion non-binding cash offer for Starwood, one-upping the merger bid that Starwood had already received from rival hotelier Marriott. Marriott's bid amounted to $12.2 billion when first made back in November, and it involved a combination of cash and Marriott stock. Market fluctuations have widened the distance between Anbang's $78 per share cash offer and the Marriott bid, but the non-binding nature of the Anbang bid could make Starwood investors reluctant to turn down Marriott's terms. At this point, some investors hope that Marriott will boost its previous bid, but the stock trades well below what Anbang said it might pay.

Advanced Micro Devices climbed 8% as investors got excited about the chipmaker's advances in the global virtual reality systems market. In a press release this morning, AMD revealed new advances in hardware and software to make virtual reality more prevalent in the technology world, and it unveiled a new certification program for graphics processing units to simplify the adoption of virtual reality technology among consumers and developers. Advanced Micro says that it has about an 83% market share in home entertainment virtual reality systems globally, and virtual reality-capable gaming consoles powered by AMD technology are in millions of homes across the world. With key partnerships with makers of popular virtual reality headsets like the Oculus Rift, AMD's Radeon ecosystem is establishing itself as a first-mover in the virtual reality space.

Finally, GW Pharmaceuticals more than doubled on Monday, finishing the day up 120%. The company said this morning that a phase 3 study of its Epidiolex investigational medicine for treating Dravet syndrome achieved its primary endpoint, significantly reducing convulsive seizures associated with the rare form of epilepsy. In investors' eyes, the announcement validated GW Pharma's use of pharmaceutical cannabidiol, and many seem to believe that further potential uses of Epidiolex for treating others forms of epilepsy, including Lennox-Gastaut Syndrome and Tuberous Sclerosis Complex, could add up to long-term success for the company. The move marks a huge reversal of fortune for GW Pharma, which had seen its shares lose two-thirds of their value since last summer because of a loss of confidence in marijuana-related stocks generally.