In my opinion Bitmex does not make any effect with price of Bitcoin because when we trade there we are not really make transaction with real physical Bitcoin. We make deposit by Bitcoin and use that BTC to buy contract, just similar like trading on the metatrader platform.
Ok so in fact we buy for REAL MONEY physical Bitcoin....
This Money is around 1,000,000,000 $ every day ( Total btc volume 5,500,000,000 $ , Bitmex is 18% so 5.500.000.000$ x 0.18 = around 1.000.000.000$)
If Bitmex will be closed today and traders from Bitmex will buying and holding real Bitcoin then they can buy every day around 270 000 btc ( around 1,6 % of total btc supply)
So in my opinion when someone closed Bitmex today then we can make in 2 months run on BTC price from 3700 to 7200 $ ( 60 x 1,6 = 95% , 3700 x 1,95=7200 )
Someone will say now " It's don't work like that " , " Bitmex had nothing to do with btc price " , But facts are very real, too much times dumping on btc prices started on bitmex.
And think. What Bitmex do with btc which is deposited and loosed by owner . They sell it.... what can it cause ?