Company: PTY
Filing Date: 2025-06-06
Form Type: 424B5
Source: 0001193125-25-137029
Chunk: 164

Company: PIMCO CORPORATE & INCOME OPPORTUNITY FUND
Filing Date: 2025-06-06
Form: 424B5
Chunk 164
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-backed and asset-backed instruments, offering investors various maturity and credit risk characteristics. Tranches are categorized as senior, mezzanine, and subordinated/equity or “first loss,” according to their degree of risk. The most senior tranche of a mortgage-backed or asset-backed instrument has the greatest collateralization and pays the lowest interest rate. If there are defaults or the collateral otherwise underperforms, scheduled payments to senior tranches take precedence over those of mezzanine tranches, and scheduled payments to mezzanine tranches take precedence over those to subordinated/equity tranches. Lower tranches represent lower degrees of credit quality and pay higher interest rates intended to compensate for the attendant risks. The return on the lower tranches is especially sensitive to the rate of defaults in the collateral pool. The lowest tranche (i.e., the “equity” or “residual” tranche) specifically receives the residual interest payments (i.e., money that is left over after the higher tranches have been paid and expenses of the issuing entities have been paid) rather than a fixed interest rate. The

September 28, 2023 | Base Prospectus 61

PIMCO Corporate & Income Opportunity Fund

Fund may also invest in the residual or equity tranches of mortgage-related and other asset-backed instruments, which may be referred to as subordinate mortgage-backed or asset-backed instruments and interest-only mortgage-backed or asset-backed instruments. The Fund expects that investments in subordinate mortgage-backed and other asset-backed instruments will be subject to risks arising from delinquencies and foreclosures, thereby exposing its investment portfolio to potential losses. Subordinate securities of mortgage-backed and other asset-backed instruments are also subject to greater credit risk than those mortgage-backed or other asset-backed instruments that are more highly rated. The mortgage markets in the United States and in various foreign countries have experienced extreme difficulties in the past that adversely affected the performance and market value of certain of the Fund’s mortgage-related investments. Delinquencies and losses on residential and commercial mortgage loans (especially subprime and second-lien mortgage loans) may increase, and a decline in or flattening of housing and other real property values may exacerbate such delinquencies and losses. In addition, reduced investor demand for mortgage loans and mortgage-related securities and increased investor yield requirements have caused limited liquidity in the secondary market for mortgage-related securities, which can adversely affect the market value of mortgage-related securities. It is possible that such limited liquidity in such secondary markets could continue or worsen. Mortgage-Related Der