While there has been unofficial price drops on Xbox One in the US as of late (most notably Amazon offering the new console at $399, then back to $450 with Titanfall bundled) - once the official Microsoft store dropped its price to $449.99 there's really no denying a price drop. While not an official price drop yet, this is a close to an official price drop you get without a press release to go with it.
Microsoft have already dropped the price in the UK by £30, but with the US dropping $50 from the price, it's clear that Microsoft wants to see sales improve as they struggle to keep up with PlayStation 4.