India’s Sterlite has increased its offer for North American miner Asarco to almost $2.6 billion in cash from about $2.1 billion, according to a letter from its legal counsel, Baker Botts.

The offer, the latest in a bidding war it is fighting with Grupo Mexico, is 63% higher than the $1.1bn in cash and notes Sterlite offered for the asset in March. Baker Botts says it also objects to a bankruptcy judge’s opinion that Grupo Mexico’s plan is the most suitable to sponsor Asarco out of Chapter 11, noting the decision “unduly discounts the overwhelming creditor preferences for [Sterlite’s] plan, underestimates the potential for labor strife if [Grupo Mexico’s] plan is confirmed while overestimating the feasibility of that plan, and disregards [Grupo Mexico’s] improper conduct both pre- and post-petition.”