The delay was a blow to Square Enix stock prices, and it was made right down to the wire before it's previous March release.
Square Enix executive Yoichi Wada explained, "The decision to delay Dragon Quest IX was made at the very last minute." The cause, as has been previously mentioned, were fatal bugs.
It was discovered in the quality control check Square Enix performed after the game's development had ended. "The bug check process," Wada said, "is no different from what other companies perform." However, Square Enix said it must strengthen its process for finding bugs.