Shareholders of GT Advanced Technologies are lobbying regulators to form a committee to vouch for their interests in the sapphire maker's bankruptcy, saying that they believe their shares may still have value, Reuters reported yesterday. GT Advanced, which supplied sapphire to Apple Inc., filed for chapter 11 protection this month under mysterious circumstances, sending shares plummeting. The case boggled the minds of market analysts when GT refused to explain why it had imploded, citing confidentiality clauses in its Apple contracts. While shareholders are typically wiped out in bankruptcy, GT Advanced stockholders believe their equity may not be worthless. Some are reaching out to the U.S. Department of Justice's bankruptcy regulator, the U.S. Trustee Program, asking it to form a committee in GT's bankruptcy to represent shareholder interests. According to a source close to the effort, law firm Brown Rudnick, which routinely represents creditors in big chapter 11 cases, is drafting a letter to the Trustee on behalf of a shareholder group requesting a committee.