Feb 13 (Reuters) - Delta Air Lines Inc raised its offer to buy up to 32 percent of Grupo Aeromexico SAB de CV by more than a fifth on Monday, valuing the deal at about $590 million.
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 ($2.15) per share.
The 53 Mexican pesos per share deal represents a premium of 34.4 percent to Aeromexico's Friday close.
Aeromexico had about 707.8 million shares outstanding as of Jan. 25, according to Thomson Reuters data.
The Mexican airline's shares rose as much as 21.5 percent to 47.90 Mexican pesos in morning trading.
The increase in the purchase price was the result of interim exchange rate movements and other factors, Delta said.
If Delta exercises the share purchase options it holds, the stake could go up to 49 percent, the company said. ($1 = 20.3150 Mexican pesos) (Reporting by Arunima Banerjee in Bengaluru; Editing by Martina D'Couto)