SANTIAGO, Nov 12 (Reuters) - Newly merged regional carrier LATAM Airlines posted a $63.7 million net loss for the third quarter on Monday, as a corporate tax rise in Chile and costs associated with the merger stung the carrier's bottom line. Chile's LAN Airlines completed a takeover of Brazilian rival TAM in June, creating the world's second-largest airline by market value in a deal that executives expect to yield up to $700 million in annual cost savings within four years. LATAM Airlines said that, in the third quarter, it faced non-recurring costs of $70.4 million due to the Chilean tax reform that permanently increased the tax rate on businesses to 20 percent, and expenditures of $19.5 million related to the merger. In September, Chile's Congress approved major changes in tax laws to provide funds for an overhaul of the country's protest-hit schools. The airline's revenue, however, more than doubled to $3.265 billion in the July to September period from $1.455 billion in the same year ago period. LATAM Airlines said it plans to spend $9.14 billion to increase its total fleet to 379 aircraft in 2015 from 323 planes in 2012.