My answer from chat:
I wouldn't close it, I would drop my tax rate to zero if it wasn't already. That will cause the corp value to shoot up. Last I recall, (10 yrs ago), that alone would scuttle the deal as the bid increases would not keep up. Thus the bid would fail since it has to be more than corp value. If they did get the corp, then raise the taxes to to 100, and wait for the value to drop and then buy it back. Above else enable CEO blocking.