Twitter LogoUPDATE, 2:03 PM: It turns out plenty of investors listened to Macquarie Captial analyst Ben Schachter, who downgraded Twitter‘s stock this morning. Shares finished the Friday session down a whopping 13% to $63.75. They had started the day at $73.71 after hitting an all-time high Thursday. Today’s losses push the company’s market cap in one day from $41.6B to $34.7B.

PREVIOUS, 8:42 AM: Twitter‘s market value increased by $11 billion just seconds after its stock began trading on the New York Stock Exchange on November 7, when the IPO launched at $26 a share. The social media darling has almost tripled that opening price and hasn’t really looked back — until today. Macquarie Captial analyst Ben Schachter lowered his rating on the stock from “neutral” to “underperform”, cooling the share price by more than 6% so far in morning trading. According to Bloomberg, the downgrade isn’t because Schachter isn’t a believer — he just believes “nothing has changed over the last 15 days to justify the rise in valuation.” He had initiated coverage December 11 with a $46 price target, and Twitter shares ended yesterday at almost $75 a pop. Bloomberg says that valued the company at $41.6 billion — bigger than Big Media heavyweights like Time Warner Cable and Viacom. Investors still put a higher value on new media companies like Yahoo and Facebook, and for Twitter the Street is bullish on mobile ad sales, a major driver of the stock to date for a company that has yet to turn a profit. Schachter isn’t the first analyst to pump the breaks on Twitter: Pivotal Research Group’s Brian Wieser downgrade the company to “sell” from “buy” on Day 1 of the IPO based on the 75%+ jump in the share price. “Twitter is simply too expensive” after it passed the high 30s, he said.

Related: Is Twitter More Valuable Than Dish Network, SiriusXM, Or Netflix?