Five top executives at GT Advanced Technologies, the New Hampshire company that was to supply Apple with scratch-resistant sapphire, including its CEO and COO, cashed in stock worth more than $10 million in the five months before the company declared bankruptcy on Oct. 6, according to regulatory filings.

Two of the five executives unloaded shares just one day before Apple unveiled the iPhone 6 and iPhone 6 Plus, which some analysts had expected would use sapphire as a replacement for the special glass that covers their touchscreens.

According to filings with the U.S. Securities and Exchange Commission (SEC), GT CEO Thomas Gutierrez sold more than 264,000 shares between May 1 and Sept. 8, pocketing over $4.5 million from four sets of transactions in May, June, July and September.

The CEO's final transaction prior to the bankruptcy filing was on Sept. 8, the day before Apple introduced the iPhone 6 and 6 Plus, when he sold 9,232 shares for over $160,000.

All of Gutierrez's stock sales during the May through September period were done under a plan he had established in mid-March "in order to implement a plan of financial diversification." Under SEC rules, insiders who file such plans -- dubbed a Rule 10b5-1 Plan -- are able to set future dates for share sales or minimum and maximum prices at which the sales are to be executed.

GT's filing, however, claimed that the former was not in play for Gutierrez. "The reporting person had no discretion with regard to the timing of the transaction," the various Form 4 submissions for Gutierrez stated.

Daniel Squiller, GT's chief operating officer, sold more than 121,000 shares during the same five-month stretch, receiving more than $2 million in return. Like Gutierrez, Squiller had put a sales plan in place, but considerably later, on May 27.

Squiller's last pre-bankruptcy transaction was conducted on Sept. 2, when he sold 15,000 shares for $270,000.

Third on the list of GT's top five executives was Hoil Kim, GT's general counsel and chief administrative officer, who sold more than 78,000 shares for more than $1.3 million. Kim's last transaction was Sept. 8, the same day as Gutierrez, when he unloaded 3,516 shares for just over $61,000.

Kim had set up a Rule 10b5-1 Plan in December 2013.

Two other vice presidents, Jeffery Ford, GT's top executive in China, and David Keck, who leads all sales at the company, sold shares between May and September as well.

Ford sold nearly 86,000 shares for more than $1.2 million in the five-month span. His last transaction was Aug. 7. Unlike Gutierrez and Squiller, Ford's Form 4 filings said nothing about a predetermined Rule 10b5-1 Plan, indicating that Ford was able to choose when he wanted to sell.

Keck, meanwhile, sold more than 61,000 shares for a total of almost $927,000 on Aug. 7. Like Ford, Keck had no Rule 10b5-1 Plan in place.

Of the seven executives listed on GT's management team page, only two -- CFO Raja Bal and CTO P.S. Raghavan -- sold no shares.

The timing of the executive stock sales has come under scrutiny because of various warning signs that the company's deal with Apple -- which pre-paid GT $578 million in several installments for the sapphire material, that money to be spent on equipment to fill a Mesa, Ariz. factory -- was not going according to plan.

According to other SEC filings by GT, Apple's third payment of $103 million was due to GT in February, but was not paid until April, while the final installment of $139 million, which was originally due in April, was postponed. In an August 7 conference call with Wall Street, GT said it expected the payment by the end of October.