Spirit Airlines will formally advise shareholders on its view of JetBlue's hostile takeover effort within 10 business days.
The Spirit board will provide its thoughts via a Security and Exchange Commission regulatory filing.
"Consistent with its fiduciary duties and applicable law, and in consultation with outside financial and legal advisors, the Spirit board of directors will carefully review JetBlue's tender offer to determine the course of action that it believes is in the best interests of Spirit and its stockholders," the company said in a prepared statement Monday afternoon.
"Spirit stockholders are urged to take no action with respect to the JetBlue tender offer at this time pending the board's evaluation of the offer."
JetBlue announced early Monday that it would offer $30 per share to Spirit shareholders and urged those investors to reject the $2.9 billion acquisition offer of Frontier Airlines that the Spirit board supports. Spirit shareholders will take a vote on whether to approve that Frontier offer on June 10.
Under the merger agreement between Spirit and Frontier, Spirit investors would receive 1.9126 shares of Frontier stock, plus $2.13 for each of their Spirit shares. Frontier stock closed Monday at $9.23.
JetBlue offered $33 per Spirit share in its initial offer on April 5. But the Spirit board rejected the offer, saying that the risk that antitrust regulators at the Justice Department would block such a merger was too high. The DOJ is currently suing JetBlue in an effort to break up its Northeast Alliance with American Airlines.
JetBlue says it is still willing to pay $33 per share if Spirit returns to the negotiating table.