One hypothesis for OSTK spike
The obvious related event is the BTC spike. Even though it doesn't make much sense. Stock market is not about picking the most beautiful contestant but figuring out who the judges will choose, based on their prejudices.
But why a spike now? I imagine a lot of BTC and OSTK accounts are sitting on tax liabilities for 2017, due to the elevated levels at the end of 2017 (if they sold into rally). And in order to write the check, they would have to sell a lot more of same at the recent depressed prices. Tax day is next Tuesday, today's trades settle the day before.
So either this is happening and/or there are a lot of other players betting on it happening. Which amounts to same thing.