Pandora has been the topic of takeover rumors for some time, as the internet radio service looks to make a swift exit from a market increasingly stifled by Spotify, Apple and Amazon. Pandora now looks to have found a suitable buyer, and surprisingly it’s none of the big three mentioned – instead, US pay radio broadcaster Sirius XM looks set to pounce. Pandora is valued at around $3 billion, and sources have suggested Sirius XM offered some $3.4 billion for Pandora earlier this year. Clearly this bid did not quite cut the mustard, so SirusXM may be preparing an offer closer to the $4 billion mark. It’s worth noting that SirusXM itself is in a fight to escape the clutches…