PIMCO Corporate & Income Opportunity Fund, managed by Allianz Global Investors Fund Management LLC and co-managed by Pacific Investment Management Company LLC, is a closed-ended fixed income mutual fund that invests in corporate debt obligations in global markets. The fund primarily focuses on intermediate maturity bonds across various sectors and uses fundamental analysis and in-house research to make its investments. Founded in 2002 and based in the United States, the fund invests in the highest non-investment grade category Ba or BB and the lowest investment grade category Baa or BBB.