Quote from Lawrence Chan:
Op ex and contract roll over in play. Nothing to do with the stock itself.
Quote from riskymove:
You think a ratings downgrade on one of the biggest stocks (well maybe not by mkt cap anymore!) stocks in the market has not effect? Totally disagree. Just look at the premarket volume as soon as the news hit. Rollover will definitely affect market as a whole today but given it still has another week to work itself out I don't believe the effects on individual names are going to be as pronounced until mid next week.