Billionaire hedge fund manager Bill Ackman is bringing in legal heavy hitters to defend his company in a lawsuit that could have major implications for special purpose acquisition companies, or SPACs.

Kaplan Hecker & Fink partners Roberta A. Kaplan, John C. Quinn and Jenna M. Dabbs have stepped in to defend the sponsors of Pershing Square Tontine Holdings in a legal action that challenges the structure of special purpose acquisition companies. The lawsuit, filed Aug. 17 in New York Southern District Court, seeks declaratory judgment that the SPAC is an investment company as defined by the Investment Company Act of 1940. The suit is backed Susman Godfrey and Bernstein Litowitz Berger & Grossman as well as former SEC commissioner Robert Jackson and Yale law professor John Morley. The case, assigned to U.S. District Judge Analisa Torres, is 1:21-cv-06907, Assad v. Pershing Square Tontine Holdings Ltd. et al.