I think you nailed it with your assumption, that they got squeezed. And all the others too. Got hacked my arse. For the first time ever I used Openledger today, time to get used to it.
Do you think POLO is shorting their customers, or has special deals with big players? Its shocking to see how they play the Ethereum madness. And to me it always looked as if they were going naked against a lot of coins.