On June 24, Frontier Airlines raised its offer for Spirit by $2. The offer is now for $4.12 in cash plus 1.9126 shares of Frontier. Total value of the offer would be $24.28 based on Frontier's closing price on Friday June 24. Frontier also raised its breakup fee to $350 million, matching JetBlue.
On June 6, JetBlue raised its bid for Spirit Airlines to $31.50 from $30.00. This offer is still a 30% premium over Frontier's enhanced offer.
Here's an analysis of the proposed deal, in the context of Similarweb traffic estimates.