Warrior Met Coal Inc. /zigman2/quotes/208793752/composite HCC -1.17% said Tuesday that some of its existing shareholders are planning to offer 8 million of the company's shares in a secondary offering underwritten by Credit Suisse. The company said it is planning to repurchase 500,000 of those shares as part of a previously-announced share buyback program. The selling shareholders will receive all of the proceeds of the secondary offering. Warrior Met Coal is a producer of hard coking coal that went public in April, 2017. Shares tumbled 7% in premarket trade, but have gained 53% in the last 12 months, while the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.11% has gained 11%.