Subject: Re: Liberty SiriusXM Group
It's really not an arbitrage for Ted Weschler. He isn't short SIRI (he is actually long a few shares).

There are no natural buyers for SIRI stock (unless you are specifically covering a SIRI short position) because the Liberty Sirius shares are available at a discount and will collapse into the same security very soon.

As mentioned here previously, you cannot short SIRI inexpensively and there have already been one or two sudden short squeezes.