Shares of leading resale goods franchisor Winmark (WINA -0.72%) were down 16% this week as of 12:30 p.m. ET Thursday, according to data provided by S&P Global Market Intelligence.As of this writing, there appears to be no direct Winmark-related news causing the steady decline in share price. While this lack of news isn't uncommon for the notoriously quiet operator -- CEO Brett Heffes typically only offers a one-sentence comment on each quarter's results -- the 16% drop is eye-catching.Ultimately, however, I ...