Apple bought a 3.6 percent stake in Imagination Technologies in 2008 and increased its ownership to around 9.5 percent in 2009. At present, Imagination Technologies is valued around $712 million so it would be a relatively small purchase for Apple.
Picking up Imagination Technologies, which currently has a market capitalisation of about £500 million, would mean that Apple could move GPU design in-house, too. Apple already works quite closely with Imagination to ensure that the PowerVR GPUs work well with other blocks on the SoC, but it may be desirable for Apple to have the whole thing in-house—to be the master of its own destiny, so to speak, and not beholden to the throes of a relatively small British company for its graphics tech.Source: ARS Technica