The board rift was disclosed in a securities filing Tuesday.
Mr. Mulacek holds shares worth more than $25 million, according to securities filings.
The refund loan business, Block has said in securities filings and court papers, is aimed at low-income people.
Consider Tiger Management, which held about $7 billion in stocks at the end of last year, according to securities filings.
By last year, according to its Federal securities filings, its loans increased to more than $1 billion.
Federal prosecutors and regulators are investigating its pay practices, according to recent securities filings.
In securities filings, the firm says going public will help it expand its products, recruit top money managers and perhaps lead to acquisitions.
It hired a consultant to interview 24 prospective buyers, but 19 expressed no interest, securities filings showed.
The consultants drew on public sources like trade publications and securities filings, these people said.
Mr. Reynolds invested $23,250 in 1980, according to the securities filings.