The U.S. will outperform major global economies in the next two years, the OECD said, but cautioned that soaring stock markets may be overestimating the pace of near-term growth. The U.S. and Canada are likely to outperform major global economies in the next two years, a prominent Paris-based think tank said Tuesday, even as it cautioned that soaring stock markets may be overestimating the pace of near-term growth.