Zac Hirzel, formerly the largest shareholder of Hawaiian Airlines’ parent company, has reduced his stake to 5.9 percent after selling 735,718 shares. Hirzel, founder and president of Dallas-based Hirzel Capital Management LLC, sold the Hawaiian Holdings Inc. shares worth nearly $18.6 million at prices ranging between $24.75 and $25.48. The transactions took place from Tuesday through Thursday. Hirzel joined Hawaiian’s board of directors in February 2014 and as of March 31 of this year was the largest shareholder with an 8.3 percent stake. Blackrock and Vanguard Group Inc. are now the largest shareholders at 8.1 percent and 7.2 percent, respectively, with Hirzel’s remaining 3.3 million shares ranking him third.