Frontier Group Holdings, Inc., the parent of Frontier Airlines (F9, Denver Int'l), has abandoned plans to hold an IPO, "at this time".

"The Company is seeking withdrawal of the Registration Statement because it is no longer pursuing an initial public offering of its common stock at this time. The Registration Statement has not been declared effective, and none of the Company’s securities have been sold pursuant to the Registration Statement," the holding said in an SEC filing.

Frontier Group Holdings filed an S-1 registration statement declaring its interest in pursing an IPO on March 31, 2017, although it never confirmed the timeline, the number of shares to be offered, or the expected proceeds.

Since 2013, Frontier Group Holdings has been owned by Indigo Partners, an Arizona-based fund with stakes in multiple low-cost carriers, such as Wizz Air (W6, Budapest), Volaris (Y4, Toluca), and JetSMART (JA, Santiago de Chile Int'l).