Spirit Airlines announced that it has commenced an underwritten public offering of 12M shares of its common stock and an underwritten public offering of $150M aggregate principal amount of convertible senior notes due 2025 . Spirit expects to use the net proceeds from the common stock offering and the convertible notes offering for general corporate purposes. Citigroup, Morgan Stanley and Barclays are acting as joint book-running managers and representatives of the underwriters for the offerings. Deutsche Bank Securities is also acting as a joint book-running manager for the offerings.