(Reuters) - A blank-check firm backed by founders of New York-based venture capital firm FirstMark Capital has filed for an initial public offering of up to $400 million. FirstMark Acquisition Corp III is offering 40 million units, consisting of stocks and warrants, at $10 each and will be listed on the New York Stock Exchange, it said in a filing. The firm will be led by Chief Executive Officer Richard Heitzmann and Chairman Amish Jani. Both Heitzmann and Jani founded FirstMark in 2008. The technology-focused VC firm has invested in image-sharing company Pinterest, fantasy-sports and gambling firm DraftKings, and home-rental company Airbnb Inc. Special purpose acquisition companies (SPACs) are shell firms that are listed on exchanges, but have no business operations. Their sole purpose is to merge with a private firm, thereby taking it public. Venture firms have joined the SPAC frenzy in recent months, as the alternative route to public markets has found favour with companies looking to sidestep a traditional IPO. Khosla Ventures, General Catalyst and Ribbit Capital have all launched blank-check firms. Credit Suisse is the sole bookrunner for the offering.