†Source: Standard & Poor’s. A credit rating is an assessment provided by a nationally recognized statistical rating organization (NRSRO) of the creditworthiness of an issuer with respect to debt obligations, including specific securities, money market instruments or other debts. Ratings are measured on a scale that generally ranges from AAA (highest) to D (lowest); ratings are subject to change without notice. “Non-Rated” indicates the debtor was not rated, and should not be interpreted as indicating low quality. For more information on Standard and Poor’s rating methodology, please visit standardandpoors.com and select “Understanding Ratings” under Rating Resources on the homepage.

also should be considered a speculative technique and may increase the Trust’s volatility. We believe a highly diversified pool of senior loans from the broadest spectrum of issuers and consisting of the highest credit quality available in line with portfolio objectives may provide the best risk-reward potential.

    Our credit analysts review all holdings and prospective holdings. Key consideration is given to the following:

Market conditions and your Trust

While lower-rated fixed income instruments underperformed our expectations for the fiscal year ended February 29, 2016. Loans’ senior position in the capital structure, secured status, short duration and limited energy sector exposure positioned the asset class defensively against some of the key risks influencing performance during the reporting period – mainly, the potential for elevated defaults as well as the potential for rising interest rates.

    Loans’ defensive positioning, particularly as it relates to rising interest rates, benefited the asset class when compared to fixed interest rate alternatives. The first interest rate increase has now occurred, and the path to normalization is likely to be at a slow and methodical pace. The US Federal Reserve (the Fed) specifically highlighted three parameters that contributed to its interest rate policy: (1) healthy growth in gross domestic policy (GDP), (2) low unemployment and (3) healthy inflation.

    During the reporting period, several dynamics affected the market. First, pockets of weakness weighed on the market – especially in commodity-related sectors. Second, we saw bifurcation of performance across the risk spectrum, as higher-quality rated loans outperformed lower-quality rated loans. Third, new issues priced wider than historical averages, resulting in a recalibration of secondary prices/spreads. And fourth, a weaker technical backdrop pushed spreads wider.

    Loans have been accretive – pricing at spreads far in excess of historical averages. As of February 29, 2016, with the average price in the loan market at $89.44, we believed loans represented an attractive long-term opportunity, as they pay a high level of current income and also can serve as an effective diversifier.¹ Keep in mind that diversification does not eliminate the risk of loss.

    Credit risk was a big focus during the reporting period as investors remained vigilant and the appetite for riskier deals was met with resistance. The fundamental environment remained generally healthy for loans as a slow but positive GDP growth rate supported a benign default rate. Issuers in general have used the last few years to strengthen balance sheets – improving profit margins, generating strong free cash flow, refinancing debt at cheaper rates and deleveraging. However, pockets of weakness emerged – particularly in commodity-related sectors, as

companies attempt to rationalize cost structures in order to adapt to the new price climate. Weakness also was seen in the retail sector, as consumer behavior shifted toward spending on autos, housing and experiences rather than on retail clothing. Over the reporting period, the default rate declined sharply, falling from 3.92% on February 28, 2015, to 1.41% as of February 29, 2016.¹ Loan defaults remained comfortably below their historical average of 3.15%.¹

    Energy and commodities weighed heavily on capital markets, which greatly influenced overall market returns and defaults. As of February 29, 2016, exposure to commodities was relatively low for the loan asset class at only 2.47% for energy and 1.36% for metals and mining.²

    For most of the fiscal year, technicals were stable – benefiting from supportive collateralized loan obligation (CLO) issuance and institutional allocations offsetting outflows from retail mutual funds. CLO issuance, as well as demand from institutional accounts, remained the cornerstone of the loan investor base. Technicals weakened in the final months of 2015 as CLO demand slowed and the typical buyers of lower-quality deals (i.e. hedge funds, distressed funds) were hesitant to deploy incremental risk in light of broader capital market volatility and losses taken in the energy sector early in 2015. CLO issuance of $98 billion in 2015 was well below the previous year’s record pace of $124 billion.¹ Outflows from retail mutual funds have been elevated since early 2014. Outflows from retail mutual funds persisted through February 29, 2016. The asset class’ exposure to retail mutual funds has decreased significantly with $58 billion in outflows since early 2014, representing a 90% unwind of the $63 billion of inflows experienced in 2013.³ We find this trend surprising given the potential diversification benefits of the loan asset class and the fact that institutional investors have taken the opposite tact, moving heavily into loans during this same period. We don’t think this trend of outflows is likely to reverse until there is more clarity around the pace of the continued US interest rate increases later in 2016.

    As of the close of the reporting period, leverage accounted for 31% of the Trust’s NAV plus borrowings and variable rate term preferred shares. Unlike other fixed income asset classes, using leverage in conjunction with senior loans does not involve the same degree of risk from rising short-term interest rates since the

income from senior loans generally adjusts to changes in interest rates, as do the rates which determine the Trust’s borrowing costs. However, as mentioned earlier, the use of leverage can increase the Trust’s volatility. For more information about the Trust’s use of leverage, see the Notes to Financial Statements later in this report.

    The Trust’s allocation to the electronics, buildings and real estate, and food and beverage industries were the largest contributors to Trust performance on a sector basis during the reporting period. On an individual-name basis, NTELOS, Albertsons and First Data were the most significant contributors to the Trust’s performance for the fiscal year.

    During the reporting period, the Trust’s use of leverage detracted from performance. The Trust’s oil and gas, structured financial obligations and utilities holdings were the largest detractors from performance for this fiscal year on an absolute basis. On an individual-name basis, Texas Competitive Electric Holdings, New Millennium Holdco and iHeartCommunications were the largest detractors from Trust performance for the reporting period.

    Senior secured loans are an asset class that behaves differently from many traditional fixed income investments. The interest income generated by a portfolio of senior secured loans is usually determined by a fixed credit spread over the London Interbank Offered Rate (Libor). Because senior secured loans generally have a very short duration and the coupons or interest rates are usually adjusted every 30 to 90 days as Libor changes, the yield on the portfolio adjusts. Interest rate risk refers to the tendency for traditional fixed income prices to decline when interest rates rise. For senior secured loans, however, interest rates and income are variable and the prices of loans are therefore less sensitive to interest rate changes than traditional fixed income bonds. We are monitoring interest rates, the market and economic and geopolitical factors that may impact the direction, speed and magnitude of changes to interest rates across the maturity spectrum, including the potential impact of monetary policy changes by the Fed and certain central banks. If interest rates rise, markets may experience increased volatility, which may affect the value and/or liquidity of certain of the Trust’s investments or the market price of the Trust’s common shares.

continued on page 6

    As always, we appreciate your continued participation in Invesco Senior Income Trust.

1 Source: Standard & Poor’s

2 Source: Credit Suisse

3 Source: J.P. Morgan

The views and opinions expressed in management’s discussion of Trust performance are those of Invesco Advisers, Inc. These views and opinions are subject to change at any time based on factors such as market and economic conditions. These views and opinions may not be relied upon as investment advice or recommendations, or as an offer for a particular security. The information is not a complete analysis of every aspect of any market, country, industry, security or the Trust. Statements of fact are from sources considered reliable, but Invesco Advisers, Inc. makes no representation or warranty as to their completeness or accuracy. Although historical performance is no guarantee of future results, these insights may help you understand our investment management philosophy.

See important Trust and, if applicable, index disclosures later in this report.

About indexes used in this report

Other information

In order for the Trust to pursue investment opportunities in line with its investment objective and strategies, the Board of Trustees of the Trust has approved the following changes to the Trust’s investment policies.

Effective January 29, 2016, the senior loans in the Trust’s portfolio are no longer required to at all times have a dollar-weighted average time until the next

interest rate redetermination of 90 days or less. Prime-based and federal funds rate loans reset periodically when the underlying rate resets. Libor loans reset on set dates, typically every 30 to 90 days, but not to exceed one year.

Effective December 4, 2015, the Trust may invest up to 20% of its total assets in any combination of (1) warrants and

equity securities (2) junior debt securities or securities with a lien on collateral lower than a senior claim on collateral, (3) high quality short-term debt securities, (4) credit-linked deposits and (5) Treasury Inflation Protected Securities (US TIPS) and other inflation-indexed bonds issued by the US government, its agencies or instrumentalities.

Plan benefits

You may increase your shares in your Trust easily and automatically with the Plan.

Shareholders who participate in the Plan may be able to buy shares at below-market prices when the Trust is trading at a premium to its net asset value (NAV). In addition, transaction costs are low because when new shares are issued by the Trust, there is no brokerage fee, and when shares are bought in blocks on the open market, the per share fee is shared among all participants.

You will receive a detailed account statement from Computershare Trust Company, N.A. (the Agent), which administers the Plan. The statement shows your total Distributions, date of investment, shares acquired, and price per share, as well as the total number of shares in your reinvestment account. You can also access your account at invesco.com/us.

The Agent will hold the shares it has acquired for you in safekeeping.

Who can participate in the Plan

If you own shares in your own name, your purchase will automatically enroll you in the Plan. If your shares are held in “street name” – in the name of your brokerage firm, bank, or other financial institution – you must instruct that entity to participate on your behalf. If they are unable to participate on your behalf, you may request that they reregister your shares in your own name so that you may enroll in the Plan.

How to enroll

If you haven’t participated in the Plan in the past or chose to opt out, you are still eligible to participate. Enroll by visiting invesco.com/us, by calling toll-free 800 341 2929 or by notifying us in writing at Invesco Closed-End Funds, Computershare Trust Company, N.A., P.O. Box 30170, College Station, TX 77842-3170. If you are writing to us, please include the Trust name and account number and ensure that all shareholders listed on the account sign these written instructions. Your participation in the Plan will begin with the next Distribution payable after the Agent receives your authorization, as long as they receive it before the “record date,” which is generally 10 business days before the Distribution is paid. If your authorization arrives after such record date, your participation in the Plan will begin with the following Distribution.

How the Plan works

If you choose to participate in the Plan, your Distributions will be promptly reinvested for you, automatically increasing your shares. If the Trust is trading at a share price that is equal to its NAV, you’ll pay that amount for your reinvested shares. However, if the Trust is trading above or below NAV, the price is determined by one of two ways:

Costs of the Plan

There is no direct charge to you for reinvesting Distributions because the Plan’s fees are paid by the Trust. If the Trust is trading at or above its NAV, your new shares are issued directly by the Trust and there are no brokerage charges or fees. However, if the Trust is trading at a discount, the shares are purchased on the open market, and you will pay your portion of any per share fees. These per share fees are typically less than the standard brokerage charges for individual transactions because shares are purchased for all participants in blocks, resulting in lower fees for each individual participant. Any service or per share fees are added to the purchase price. Per share fees include any applicable brokerage commissions the Agent is required to pay.

Tax implications

The automatic reinvestment of Distributions does not relieve you of any income tax that may be due on Distributions. You will receive tax information annually to help you prepare your federal income tax return.

    Invesco does not offer tax advice. The tax information contained herein is general and is not exhaustive by nature. It was not intended or written to be used, and it cannot be used, by any taxpayer for avoiding penalties that may be imposed on the taxpayer under US federal tax laws. Federal and state tax laws are complex and constantly changing. Shareholders should always consult a legal or tax adviser for information concerning their individual situation.

How to withdraw from the Plan

You may withdraw from the Plan at any time by calling 800 341 2929, by visiting invesco.com/us or by writing to Invesco Closed-End Funds, Computershare Trust Company, N.A., P.O. Box 30170, College Station, TX 77842-3170. Simply indicate that you would like to withdraw from the Plan, and be sure to include your Trust name and account number. Also, ensure that all shareholders listed on the account sign these written instructions. If you withdraw, you have three options with regard to the shares held in the Plan:

The Trust and Computershare Trust Company, N.A. may amend or terminate the Plan at any time. Participants will receive at least 30 days written notice before the effective date of any amendment. In the case of termination, Participants will receive at least 30 days written notice before the record date for the payment of any such Distributions by the Trust. In the case of amendment or termination necessary or appropriate to comply with applicable law or the rules and policies of the Securities and Exchange Commission or any other regulatory authority, such written notice will not be required.

    To obtain a complete copy of the current Dividend Reinvestment Plan, please call our Client Services department at 800 341 2929 or visit invesco.com/us.