** Shares of semiconductor parts maker AXT AXTI.O down 8% at $14.19 premarket
** Co files for common stock offering of 7.1 million shares at $12.25 apiece to certain institutional investors
** Offer price implies a 20.3% discount to stock's last close of $15.37
** AXTI expects gross proceeds of about $87 million, before other expenses
** Co intends to use net proceeds to primarily increase the capacity of subsidiary Beijing Tongmei Xtal Technology to produce indium phosphide substrates for export worldwide
** As of last close, stock up seven-fold YTD
(Reporting by Koyena Das from Bengaluru)
((Koyena.das@thomsonreuters.com))