Brazil’s Itau Unibanco Holding, Latin America’s largest bank in market value terms, has turned to Wachtell, Lipton, Rosen & Katz for counsel on a cash-and-stock bid for control of CorpBanca that Reuters values at nearly $3.7 billion. The target, Chile’s fifth-largest bank, has retained the services of Simpson Thacher & Bartlett and a pair of South American firms.

The transaction’s terms call for CorpBanca to merge its Chilean assets with Itau’s local affiliate, which will receive a $652 million investment from its Brazilian parent on the way to creating a new entity owned by the two banks, according to Bloomberg. The two banks had been in discussions for several weeks about a potential partnership.