Delta Air Lines Inc. said on Monday it plans to launch a cash tender offer to buy up to an additional 32 percent of Grupo Aeromexico SAB de CV's stock at 53 Mexican pesos per share, valuing the deal at about $590 million.
The offer represents a premium of 34.4 percent to Aeromexico's Friday close.
The Mexican airline's shares rose as much as 21.5 percent to 47.90 Mexican pesos in morning trading.
Delta, which already has a 4.2 percent stake in Aeromexico, had said in November 2015 it intended to buy the additional stake for 43.59 Mexican pesos per share.
Aeromexico had about 707.8 million shares outstanding as of Jan. 25, according to Thomson Reuters data.
The increase in the purchase price was the result of interim exchange rate movements and other factors, Delta said on Monday.
The Mexican peso has hit a series of record lows since the U.S. election on concerns that President Donald Trump could rip up a free trade deal with Mexico, which sends nearly 80 percent of its exports to its northern neighbor.
If Delta exercises the share purchase options it holds, the stake could go up to 49 percent, the company said.