An arbitrage opportunity for institutions? Nope
Arbitrage by definition means taking advantage of pricing discrepancies. So if you buy the futures now, what do you simultaneously sell to lock in the profit?
This gap will be there tomorrow when the market is open, just talking out loud here, but why not buy the futures, and sell the 30 dow stocks until the gap "narrows" as a 30-60 point gap is more normal from my experience, this just seemed like too big a gap that needs to tighten up, and will over the next week, one way or the other, either futures come up to the dow cash, or cash comes down to the futures.
Obviously by the time the june contract ends, rolls over, you cannot have a 100 point difference, so the gap has to close.