RE: Perplexing It's well documented that FIS trades at roughly a 15-20c discount, you're right about that. What you're missing though is the leverage to PLS. While the DML deal is still outstanding, FIS can't move a much as AMW for two reasons: 1) FIS has a bigger market cap so a $20mm move in market cap isn't as big of a % move as it is for AMW, and 2) the DML deal likely doesn't close until April and arb deals always have a spread until the day they close. One day, that valuation gap will close, but in the meantime people that want direct PLS leverage are buying AMW and the AMW float is incredibly tight. When the FIS/AMW "arb-gap" closes, it will happen in about a day, but there's so much news to come between now and then that it could be a lot higher by that point depending on results.
It's all about potential % moves and leverage. AMW is the only way to measure the value of the FIS spinco, so it will always trade at a premium until the deal closes, which should be in 2-2.5 months.