S&P 500 futures are down 24 points, or 0.5% ahead of the open. Futures were flat an hour ago but the selling has picked up in the past 30 minutes.

There are two worries:

1) Adobe shares are down 12% in the pre-market. This is the first real earnings crack in a high-flying AI stock.

2) It's quad witching so this could be mostly mechanical.

The drop should have the index opening near yesterday's lows.

Spoos