The bidding war over Signature Aviation, the largest FBO chain, is continuing to unfold with the latest offer of $4.7 billion coming from a partnership of rival bidders.

Last month, Signature's board agreed to a $4.6 billion bid from GIP that edged out a previous offer from the Blackstone Group and Cascade Investment, the latter of which manages much of Microsoft co-founder Bill Gates’s personal fortune and has a nearly 20 percent stake in Signature. When Signature accepted the $5.50 per share GIP offer, the FBO operator noted that it would continue to review offers, leading the two bidding groups to join and improve the offer to $5.62 a share.

While the Carlyle Group, which had owned the former Landmark Aviation FBO chain before selling it to Signature, could still weigh in with an offer of its own, this new combined cash offer—if consummated—would give Blackstone and GIP each a 35 percent ownership stake in Signature, while Cascade would increase its share from 19 to 30 percent. As with the previously accepted offer, the deal is subject to legal review and the approval of at least 75 percent of Signature's shareholders. 

Signature Flight Support has more than 200 locations worldwide, and the deal also includes its Epic Fuels subsidiary, as well as the company's engine repair business that Signature Aviation has been attempting to unload.