Company: PTY
Filing Date: 2025-06-06
Form Type: 424B5
Source: 0001193125-25-137029
Chunk: 155

Company: PIMCO CORPORATE & INCOME OPPORTUNITY FUND
Filing Date: 2025-06-06
Form: 424B5
Chunk 155
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 such as covered credit default swaps or other derivative instruments. These assumed investment portfolio returns in the table below are hypothetical figures and are not necessarily indicative of the investment portfolio returns experienced or expected to be experienced by the Fund. Your actual returns may be greater or less than those appearing below. In addition, actual borrowing expenses associated with reverse repurchase agreements (or dollar rolls/buy backs or borrowings, if any) used by the Fund may vary frequently and may be significantly higher or lower than the rate used for the example below.

| Assumed Return on Portfolio (Net ofExpenses) | (10.00)% | (5.00)%  | 0.00%   | 5.00% | 10.00% |
| Corresponding Return to CommonShareholders   | (17.44)% | (10.05)% | (2.66)% | 4.73% | 12.12% |

Common Share total return is composed of two elements — the Common Share dividends paid by the Fund (the amount of which is largely determined by the net investment income of the Fund after paying dividends on Preferred Shares and expenses on any forms of leverage outstanding) and gains or losses on the value of the securities and other instruments the Fund owns. As required by SEC rules, the table assumes that the Fund is more likely to suffer capital losses than to enjoy capital appreciation. For example, to assume a total return of 0%, the Fund must assume that the income it receives on its investments is entirely offset by losses in the value of those investments. This table reflects hypothetical performance of the Fund’s portfolio and not the actual performance of the Fund’s Common Shares, the value of which is determined by market forces and other factors. Should the Fund elect to add additional leverage to its portfolio, any benefits of such additional leverage cannot be fully achieved until the proceeds resulting from the use of such leverage have been received by the Fund and invested in accordance with the Fund’s investment objective and policies. As noted above, the Fund’s willingness to use additional leverage, and the extent to which leverage is used at any time, will depend on many factors, including, among other things, PIMCO’s assessment of the yield curve environment, interest rate trends, market conditions and other factors. Principal Risks of the Fund The Fund is subject to the principal risks noted below, whether through the Fund’s direct investments or derivatives positions.

Market Discount Risk The price of the Fund’s Common Shares will fluctuate with market conditions and other factors. If you