(Reuters) - Two blank-check firms, backed by veteran Wall Street dealmaker Michael Klein, are looking to raise a total of $700 million through initial public offerings, regulatory filings showed on Monday. The shell companies, known as Churchill Capital Corp VI and VII, are looking to raise $400 million and $300 million, respectively, by selling units, shares and warrants on the New York Stock Exchange. Blank-check firms, also known as special purpose acquisition companies (SPAC), typically raise money in an IPO to pursue an acquisition without telling their investors in advance which specific company they will buy. Klein’s fifth SPAC, Churchill Capital Corp V, had upsized its IPO to $400 million in October. Some of Klein’s blank-check firms have already struck deals. Last year, healthcare services provider MultiPlan signed an $11 billion deal to go public by merging with another entity of Churchill Capital. Apart from Klein, a former Citigroup banker, other high-profile investors such as Chamath Palihapitiya and Bill Ackman, have raised billions of dollars through their SPACs, with Ackman"s SPAC raising a record $4 billion in July. (reut.rs/3bFE61J) J.P. Morgan, Citigroup, Goldman Sachs and BofA securities are acting as the lead underwriters for both IPOs.