Update: This is what drove it we suspect:

  • WEXTON WINS VIRGINIA HOUSE RACE, FIRST PICKUP FOR DEMOCRATS

However, Democrat Jennifer Wexton's win in Virginia was expected. And though it'll cheer Democrats as an early pickup seat in the House, it may not be much of a bellwether.

Only 23 more to go...

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While it is hard to discern exactly what drove this sudden shift towards a 'blue wave'-themed derisking in markets, Dow futures are down 100 points...

10Y yields are down 3bps...

and the dollar tumbled...

And gold is bid...

We don't have much data to work with so far, but we're starting to see slight movement in FiveThirtyEight's real-time forecast. They're now projecting Democrats have a 11 in 12 chance to win the House (a slight improvement) while they have just a 1 in 7 chance to win the Senate.