A lot of people wondering who is selling now at these prices. Sounds insane with a 420 offer on the table.
Let me speculate a bit...
A lot of leveraged longs stated that they are exiting their long-term high price call options, as those are losing value (should go to 0 if their date/price is beyond the deal closing time/value). Now, we can assume most of those call options were written and sold by MMs. At the time they sold them, they probably bought some shares to hedge the option sale, they probably do not risk naked options. Now, when the options are bought back, they can sell the shares (at some profit as the SP is now higher). This is done by algobots, solid general logic, making profits so why not ? Except, this time there is a looming 420 offer on the table, so it would make sense to hold them, but there is no human oversight and the bots are not programmed to take into account twitter-rumors
So, there, you do not need short sellers or stupidity to explain selling pressure below 420...