 SmileDirectClub Inc. SDC, shares tanked more than 20 in the extended session Monday after the maker of clear plastic aligners reported a wider quarterly loss and sales missed the mark, saying it ran against macroeconomic headwinds. SmileDirect lost 89 million, or 23 cents a share, in the third quarter, compared with 13 million, or 11 cents a share, in the year-ago period. 