ARM saw its shares rise 7% to an all-time high on Tuesday, heading the UK top-flight gainers, following renewed takeover speculation involving Intel and Apple.
Shares for the Cambridge-based microchip designer closed up 29 at 366.8p to lead the FTSE 100 index on Tuesday. Currently, ARM has a market value of £4.83 billion.
ARM has long been rumoured as a take over target for Apple, as the company makes the A4 chip found in the iPad and iPhone 4.
Speculation of a takeover increased this week as Intel acquired the wireless semiconductor business of Germany's Infineon for £911 million ($1.7 billion). Infineon uses ARM chip designs.
Intel and Apple have long been rumoured to be interested in buying ARM. However ARM's chief executive Warren East has dismissed the rumours, insisting Apple and Intel do not need to buy ARM in order to use its designs.
ARM designs the microchips found in virtually all of the world's smartphones, including Apple's iPhone and iPad.