Bill Ackman is not a stupid man. He’s an activist investor, which means he pressures companies to take on debt or close factories. He’s made $3.1 billion from it.  So why did Ackman dive headfirst into the special purpose acquisition company (SPAC) business one year ago? SPACs do not have a good reputation.  The short answer is that Ackman stood to make $800 million from one SPAC deal – if he could pull it off. But it looks like he got greedy. The SPAC boom is now over. In trying to land the biggest SPAC deal ever, it looks like…