A lawsuit filed by investors against a major special-purpose acquisition company has gotten quite the reaction from Big Law, which has found SPACs to be lucrative business drivers over the past 18 months. 

Pershing Square Tontine Holdings, the special purpose acquisition company run by billionaire hedge-fund manager Bill Ackman, was served with a shareholder lawsuit Aug. 17, where the plaintiffs are seeking a declaratory judgement that under the Investment Company Act of 1940, SPACs should be considered investment companies.