Shares of GT Advanced Technology have fallen since Sept. 9, when Apple said it wouldn’t use sapphire screens in its new iPhones.

One day before Apple AAPL +0.24% announced that its new iPhones would not use sapphire screens made by GT Advanced Technologies GTAT +17.25%, the supplier’s chief executive sold more than 9,000 shares of GT stock, for $160,000.

GT CEO Thomas Gutierrez sold the shares Sept. 8 at an average price of $17.38. The next day, after Apple’s announcement, GT shares fell 13% to $14.94.

Monday, GT filed for bankruptcy protection, sending its shares down 93% to 80 cents.

Prior to Apple’s iPhone announcement, GT shares had more than doubled over the previous 12 months, fueled by optimism that a partnership with Apple could deliver big rewards for the company.

In a filing, GT said Gutierrez’s share sale was part of a pre-arranged plan put in place on March 14, 2014. But there was no obvious pattern to his sales.

In May, June and July, Gutierrez sold shares within the first three days of the month. But then he didn’t sell additional shares until Sept. 8, two days after he received 15,902 previously restricted shares. (Gutierrez forfeited the remaining 6,670 shares to cover tax obligations.)

Gutierrez didn’t sell any shares in 2013. This year, he’s sold nearly 700,000 shares since February, valued at more than $10 million.

A GT spokesman didn’t return calls for comment.