 ThredUp Inc. TDUP, 7.55 shares fell more than 11 in the extended session Monday after the secondhand retailer posted mixed quarterly results and guided for lower first-quarter sales. ThredUp said it lost 17.9 million, or 18 cents a share, in the fourth quarter, compared with a loss of 17 million, or 1.33 a share, for the fourth quarter 2020. 