This is a company that's essentially had multiple parts of it for sale for the better part of 4 years and this hasn't once come out.
I'm running through all the Yahoo corporate filings that Bloomberg has indexed and I can't find any link to this clause.
I mean this is a very material issue!
If you are to be a share holder in a company that's trying to broker a 3-4 Billion sale of some of its assets, then knowing that the buyer may be on the hook for an additional 1 billion bill probably means that the asset you thought you owned is probably worth 20-25% less than you originally thought.
Someone isn't going to be very happy with the yahoo leadership today:)