In a way, it would mean coming full circle for ARM: the company was set up in 1990 as a joint venture between Acorn Computers, Apple, and VLSI Technology as Advanced RISC Machines. Its goal was to further develop the processor found in the Archimedes. We all know the rest: the ARM architecture became the dominant low-power embedded architecture.
"A deal would make a lot of sense for Apple," one trader told the London Evening Standard, "That way, they could stop ARM's technology from ending up in everyone else's computers and gadgets." According to these traders, Apple would offer 400p a share, which would value ARM at 5.2 billion GBP.
If such a deal were to go down, it would send a massive shock wave across the industry. Considering Apple's track record, it could well be that they want to keep all the technology for themselves, giving them a massive competitive advantage over others. Apple certainly has the money for it, so that isn't a problem.
We'll have to wait and see. At this point, it's still just a rumour.