The market cap was $1.14B, now 20% higher in AH. Let's say Sycamore buys at a 25% premium: that is $1.425B: a lot of money for Sycamore, but do-able. (I guess)
So why didn't they buy ARO instead? For whatever reason, ARO just can't seem to cut its costs to generate a good return. Express's gross and net margin is much, much better, and no doubt Sycamore will keep Express management...if Sycamore wanted ARO they'd probably want to switch management and offer $8-$12 a share, since institutional holders own way over 50% of the float, and they won't want to sell at cheapskate prices.
At $8 a share for ARO that is 628M. Add two to four quarters to turn profitability around, and you are looking at another 150M. Add (good) new management plus golden parachutes for current management and that's maybe another 10M-20M.
Still a lot cheaper, but a huge headache and I'm guessing Sycamore didn't want the headache.
But who knows, maybe they'll scoop up ARO tomorrow.