I agree.
I'm currently separated from my DD, but I seem to recall that Liberty would have to acquire $7 billion to buy out the remaining 60% of SIRI. Liberty has somewhere close to $2bil available but would need to acquire the remaining 5 by manipulating their own equity or their ownerships of other public companies.
Basically Liberty could buy out SIRI after March 7, but they wouldnt need to.
They have a large stake within SIRI and no other company will overshadow that stake for quite some time.
With time we could see it be bought out by a company other than Liberty, but I stress the TIME aspect. Remember, Liberty would need an additional $7 billion and already owns approximately $5 billion of the company. If a company other than Liberty would be attempting to buyout SIRI then they would need to provide for the $12 billion combined.
JMO