ARM Holdings Plc. Omap 4 microprocessor chips, manufactured by Texas Instruments Inc., sit on display at the ARM Holdings Plc headquarters in Cambridge, U.K., on Wednesday, March 16, 2011. ARM Holdings Plc's stock has rallied so fast that the designer of chips that help power Apple Inc.'s iPhone is now the most expensive takeover target in the semiconductor industry since 2006. Photographer: Chris Ratcliffe/Bloomberg via Getty Images