Marko Kolanovic, a strategist at JPMorgan Chase, said runaway commodity prices, divergent policies from global central banks and the recent stock market sell-off had created rare buying opportunities for growth and value stocks. "the mood and position are too pessimistic," Kolanovic and Bram Kaplan wrote in a report on Tuesday. They expect the stock market to rise in the short term, especially small-cap stocks and high beta stocks, and advise investors to build a "barbell portfolio" of growth stocks including technology, biotechnology and innovation, as well as value stocks such as metals and mining.