The prospect of Exxon Mobil or Chevron buying European majors has receded after the two leading U.S. oil companies announced major acquisitions focused on the Americas this month, investors said. Speculation that Chevron and Exxon might try to buy rivals BP and Shell intensified over the last two years as the European majors underperformed their U.S. rivals. Investors punished the European companies for their pivot towards renewables and low carbon energy while rewarding the U.S. companies' focus on oil and gas production that drove record profits last year.