Have you heard about a new battery which can charge in one minute. That news came out of nowhere until then. That battery didn't have the density required so can't be used. TESLA is doing research on battery Technology every day. It just so happens one day they find the right battery which satisfies all the conditions and may not need charging for a 1000 (thousand) miles. Until that day there is no risk to shorts. What if that day is tomorrow and the news is one tweet away from Musk. There is no telling how high this will go. I think it will skip more than 100 points straight up. There is no risk for shorts until then... enjoy
After Yahoo announced that it will create SpinCo (Alibaba stake), yahoo should stop the buybacks immediately. After the spinoff core value plus yahoo Japan will be about $20. Yahoo should buyback shares at that lower price. If Yahoo continuous to buy now, it is wasting money. Alibaba part is what Yahoo is paying more now. I say wait on buybacks.