Western Asset Investment Grade Defined Opportunity Trust : Annual Report - IGI

Annual Report November 30, 2021

WESTERN ASSET INVESTMENT GRADE DEFINED OPPORTUNITY TRUST INC. (IGI)

INVESTMENT PRODUCTS: NOT FDIC INSURED • NO BANK GUARANTEE • MAY LOSE VALUE

Fund objectives

The Fund's primary investment objective is to provide current income and then to liquidate and distribute substantially all of the Fund's net assets to stockholders on or about December 2, 2024. As a secondary investment objective, the Fund will seek capital appreciation. There can be no assurance the Fund will achieve its investment objectives.

The Fund seeks to achieve its investment objectives by investing, under normal market conditions, at least 80% of its net assets in investment grade corporate fixed income securities of varying maturities.

What's inside

Letter from the chairman	III
Fund overview	1
Fund at a glance	7
Fund performance	8
Schedule of investments	10
Statement of assets and liabilities	30
Statement of operations	31
Statements of changes in net assets	32
Financial highlights	33
Notes to financial statements	34
Report of independent registered public accounting firm	48
Additional information	49
Annual chief executive officer and principal financial officer certifications	55
Other shareholder communications regarding accounting matters	56
Summary of information regarding the Fund	57
Dividend reinvestment plan	72
Important tax information	74

1. Western Asset Investment Grade Defined Opportunity Trust Inc.

Letter from the chairman

Dear Shareholder,

We are pleased to provide the annual report of Western Asset Investment Grade Defined Opportunity Trust Inc. for the twelve-month reporting period ended November 30, 2021. Please read on for a detailed look at prevailing economic and market conditions during the Fund's reporting period and to learn how those conditions have affected Fund performance.

As always, we remain committed to providing you with excellent service and a full spectrum of investment choices. We also remain committed to supplementing the support you receive from your financial advisor. One way we accomplish this is through our website, www.franklintempleton.com. Here you can gain immediate access to market and investment information, including:

• Fund prices and performance,
• Market insights and commentaries from our portfolio managers, and
• A host of educational resources.

We look forward to helping you meet your financial goals.

Sincerely,

Jane Trust, CFA

Chairman, President and Chief Executive Officer

December 31, 2021

Western Asset Investment Grade Defined Opportunity Trust Inc.

III

(This page intentionally left blank.)

Fund overview

Q. What is the Fund's investment strategy?

A. The Fund's primary investment objective is to provide current income and then to liquidate and distribute substantially all of the Fund's net assets to stockholders on or about December 2, 2024. As a secondary investment objective, the Fund will seek capital appreciation. There can be no assurance the Fund will achieve its investment objectives.

The Fund seeks to achieve its investment objectives by investing, under normal market conditions, at least 80% of its net assets in investment grade corporate fixed income securities of varying maturities. The Fund may invest up to 20% of its net assets in corporate fixed income securities of below investment grade quality (commonly known as "high yield" or "junk" bonds) at the time of investment and other securities, including obligations of the U.S. government, its agencies or instrumentalities, common stocks, warrants and depositary receipts. While the Fund may invest up to 20% of its net assets in below investment grade securities, the Fund will, under normal market conditions, maintain a portfolio with an overall dollar-weighted average of investment grade credit quality. The Fund may invest up to 20% of its net assets in securities of foreign issuers located anywhere in the world, including issuers located in emerging market countries. Additionally, the Fund may invest up to 20% of its net assets in non-U.S. dollar denominated securities.

The Fund may invest in derivative instruments, such as options contracts, futures contracts, options on futures contracts, indexed securities, credit default swaps and other swap agreements, provided that the Fund's exposure to derivative instruments, as measured by the total notional amount of all such instruments, will not exceed 20% of its net assets.

In purchasing securities and other investments for the Fund, we may take full advantage of the entire range of maturities and durations offered by corporate fixed income securities and may adjust the average maturity or duration of the Fund's portfolio from time to time, depending on our assessment of the relative yields available on securities of different maturities and durations and our expectations of future changes in interest rates.

The Fund may take on leveraging risk by utilizing certain management techniques, whereby it will segregate liquid assets, enter into offsetting transactions or own positions covering its obligations. To the extent the Fund covers its commitment under such a portfolio management technique, such instrument will not be considered a senior security for the purposes of the Investment Company Act of 1940. However, as a fundamental policy, the Fund will not leverage its capital structure by issuing senior securities such as preferred shares or debt instruments.

At Western Asset Management Company, LLC ("Western Asset"), the Fund's subadviser, we utilize a fixed income team approach, with decisions derived from interaction among various investment management sector specialists. The sector teams are comprised of Western Asset's senior portfolio management personnel, research analysts and an in-house economist. Under this team approach, management of client fixed income portfolios will reflect a consensus of interdisciplinary views within the Western Asset organization. The

Western Asset Investment Grade Defined Opportunity Trust Inc. 2021 Annual Report

1