MEXICO CITY, Dec 16 (Reuters) - Mexican carrier Aeromexico on Thursday said an unnamed third party would make a tender offer valuing its oustanding shares at a fraction of their previous market price as part of its efforts to emerge from bankruptcy. News of the planned tender offer, which would offer 0.01 peso for each outstanding share, sent its shares tumbling nearly 75%. Shares in the company, which filed for Chapter 11 bankruptcy protection in the United States last year amid the pandemic, closed at 3.89 pesos on Wednesday. They were trading at 1.84 pesos in early afternoon in Mexico. The offer gives existing shareholders the chance to withdraw from current capital stock prior to the capitalization of debts. Delta Air Lines Inc (DAL.N), which had controlled a majority of Aeromexico, would not be taking part in the offer, a statement noted, and its stake will be diluted to 20%. Aeromexico (AEROMEX.MX) gave no further details about the third party. Carlos Hernandez, senior analyst at Masari Casa de Bolsa, said ownership and management changes often spook the market. "They can represent uncertainty for investors and even more so when some financial elements are compromised," Hernandez said. "Right now, we do not have a defining position for the company." Still, Aeromexico emphasized that several of its longtime shareholders would remain with the company, including a core group of Mexican investors, with 4.1%, as well as Delta. Aeromexico"s biggest stakeholder coming out of bankrutpcy will be Apollo Global Management (APO.N), a fund which often invests in bankrupt companies, with 22.38%. Apollo last year provided Aeromexico with $1 billion in debtor-in-possession financing. Last week Aeromexico said a bankruptcy court had approved a disclosure statement regarding a plan for the reorganization of the company and its subsidiaries. Up to 331,480,713 shares are expected to be acquired under the tender offer. That would represent up to 49% of the capital stock prior to the dilution resulting from the restructuring plan, which would leave them representing less than 0.01% of the reorganized company"s outstanding shares, Aeromexico said. Equity stakeholders are frequently diluted or even wiped out entirely during Chapter 11 reorganizations, in which debt is typically swapped for equity stakes. The rest will be distributed among new investors and creditors who swap their claims for Aeromexico"s future stock, the airline said.