MEXICO CITY, Jan 6 (Reuters) - Passenger traffic at Grupo Aeromexico in December reached its highest level since the start of the COVID-19 pandemic, the Mexican airline said on Thursday.

Aeromexico transported 1.74 million passengers last month, or 98.9% of the 1.76 million people it moved in December 2019, the company said in a statement.

Aeromexico's total offer, measured in available seat-kilometers (ASKs), was equivalent to 82.6% of the capacity of December 2019, the company said.

Domestic capacity was up 13.6% from December 2019, while international capacity was 70.7% of that month.

Aeromexico filed for Chapter 11 bankruptcy protection in the United States in 2020 as demand cratered amid the pandemic. In December it unveiled details of a tender offer valuing its outstanding shares near zero as part of its reorganization plan, sparking a sell-off in the stock.

The positive traffic figures did nothing to help the airline's long-suffering stock price, as the shares slumped 6.5% to 2.31 pesos in their seventh straight daily drop. (Reporting by Valentine Hilaire; Editing by Nick Zieminski and Mark Porter)