Western Asset HIO (HIO) names new portfolio team, removes Kilpatrick by Sep 30, 2026

Rhea-AI Filing Summary

Western Asset High Income Opportunity Fund Inc. updates its Prospectus and Statement of Additional Information with portfolio manager changes effective January 27, 2026 and a later change effective September 30, 2026.

The Prospectus replaces the prior "Investment Management Team" section with a team-based description and identifies five portfolio managers responsible for day-to-day management: Michael C. Buchanan, Christopher F. Kilpatrick, Walter Kilcullen, John Hwang, and Ryan Kohan. The SAI table (as of September 30, 2025) lists each manager's other accounts and assets managed by category, and shows each manager holds Dollar Range A (none) of Fund securities as of that date.

Effective September 30, 2026, the Prospectus and SAI are further updated to remove the information relating to Christopher Kilpatrick.

Key Figures

Prospectus supplement effective date: January 27, 2026 Further supplement effective date: September 30, 2026 Michael C. Buchanan - registered company assets: $85.01 billion +3 more

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Prospectus supplement effective date January 27, 2026 Portfolio Manager Updates effective date

Further supplement effective date September 30, 2026 Date when Christopher Kilpatrick information is deleted

Michael C. Buchanan - registered company assets $85.01 billion Total assets in other registered investment companies managed, as of September 30, 2025

Michael C. Buchanan - other pooled vehicles assets $45.31 billion Total assets in other pooled vehicles managed, as of September 30, 2025

John Hwang - other pooled vehicles performance-fee assets $1.87 billion Assets managed in other pooled vehicles with performance-based fees, as of September 30, 2025

Ryan Kohan - other pooled vehicles assets $8.02 billion Total assets in other pooled vehicles managed, as of September 30, 2025

Key Terms

Statement of Additional Information (SAI), Dollar Range ownership, CLO

3 terms

Statement of Additional Information (SAI) regulatory

"The SAI table identifies the number of accounts and total assets as of September 30, 2025"

Dollar Range ownership financial

"The portfolio managers held the following amounts of securities of the Fund as of September 30, 2025"

CLO financial

"Mr. Hwang co-manages all collateralized loan obligation (CLO) portfolios"

A CLO (Collateralized Loan Obligation) is a financial vehicle that pools many corporate loans and sells slices of that pool to investors, with each slice carrying a different mix of risk and return—think of it as a loan-based fund cut into safe and risky pieces. It matters to investors because CLOs can offer higher yields than traditional bonds but expose buyers to borrowers’ defaults and changes in interest rates, so understanding which slice you own is key to gauging potential reward and loss.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 04/23/2026 - 05:18 PM Learn about SEC filing dates

FAQ

What portfolio manager changes did Western Asset HIO disclose?

The filing replaces the Investment Management Team description and names five day-to-day managers effective January 27, 2026. It later removes Christopher Kilpatrick effective September 30, 2026. The SAI shows related account and asset data as of September 30, 2025.

How many other accounts does Michael C. Buchanan manage outside the Fund (HIO)?

The SAI reports Michael C. Buchanan manages 58 other registered investment company accounts, 194 other pooled vehicles, and 285 other accounts, with total assets of $85.01 billion, $45.31 billion, and $83.15 billion, respectively, as of September 30, 2025.

What security ownership do the portfolio managers hold in the Fund?

As of September 30, 2025, each listed portfolio manager is reported in Dollar Range A, indicating none of the Fund's securities beneficially owned. The table defines Range A as none and higher ranges with explicit dollar bands.

Which managers specialize in specific credit areas for Western Asset HIO?

The Prospectus states John Hwang is a member of the high-yield desk specializing in bank loans and corporate structured credit and co-manages CLO portfolios. Ryan Kohan is identified as Head of Bank Loans with specialized experience listed in the Prospectus.

When will Christopher Kilpatrick be removed from Fund disclosures?

The supplement states the information relating to Christopher Kilpatrick is deleted from both the Prospectus and the SAI effective September 30, 2026, superseding earlier portfolio manager disclosures where inconsistent.

Filed Pursuant to Rule 424(b)(3)
Registration Statement No. 333-291121

WESTERN ASSET HIGH INCOME OPPORTUNITY FUND INC.

SUPPLEMENT DATED APRIL 23, 2026 TO THE

PROSPECTUS AND STATEMENT OF ADDITIONAL INFORMATION DATED MARCH 24, 2026

Portfolio Manager Updates Effective January 27, 2026

Effective as of January 27, 2026, the following supplements and, to the extent inconsistent with, supersedes the section entitled “Management of the Fund” in the Fund’s Prospectus (“Prospectus”) and the section entitled “Portfolio Managers” in the Fund’s Statement of Additional Information (“SAI”):

Prospectus

The information contained in “Investment Management Team” in the “Management of the Fund” section of the Prospectus is removed entirely and replaced as follows:

Investment Management Team

Set forth below is information regarding the team of professionals at Western Asset responsible for overseeing the day-to-day operations of the Fund. Western Asset utilizes a team approach, with decisions derived from interaction among various investment management sector specialists. The sector teams are comprised of Western Asset’s senior portfolio managers, research analysts and an in-house economist. Under this team approach, management of client fixed income portfolios will reflect a consensus of interdisciplinary views.

Name, Address and Title		Principal Occupation(s) During Past 5 Years
Michael C. Buchanan Western Asset 385 East Colorado Blvd. Pasadena, CA 91101		Responsible for the day-to-day management with other members of the Fund’s portfolio management team; employed by Western Asset Management as an investment professional for at least the past five years; Managing Director and head of U.S. Credit Products from 2003-2005 at Credit Suisse Asset Management.
Christopher F. Kilpatrick Western Asset 385 East Colorado Blvd. Pasadena, CA 91101		Responsible for the day-to-day management with other members of the Fund’s portfolio management team; employed by Western Asset Management as an investment professional for at least the past five years.
Walter Kilcullen Western Asset 385 East Colorado Blvd. Pasadena, CA 91101		Responsible for the day-to-day management with other members of the Fund’s portfolio management team; employed by Western Asset Management as an investment professional since 2002.
John Hwang Western Asset 385 East Colorado Blvd. Pasadena, CA 91101		Responsible for the day-to-day management with other members of the Fund’s portfolio management team; Mr. Hwang is a member of the high-yield desk and specializes in bank loans and corporate structured credit. Mr. Hwang co-manages all collateralized loan obligation (CLO) portfolios and is responsible for all corporate-structured credit investments within Western Asset. Mr. Hwang has over 24 years of investment industry experience.
Ryan Kohan Western Asset 385 East Colorado Blvd. Pasadena, CA 91101		Responsible for the day-to-day management with other members of the Fund’s portfolio management team; Mr. Kohan is Head of Bank Loans and has been employed by Western Asset as an investment professional for at least the past five years. Mr. Kohan has over 17 years of investment industry experience.

Additional information about the portfolio managers’ compensation, other accounts managed by them and other information is provided in the SAI.

SAI

The information contained in the table in the “Portfolio Managers” section of the SAI is removed entirely and replaced as follows:

Unless otherwise indicated, the information below is provided as of the date of this SAI.

The table below identifies the number of accounts (other than the Fund) for which the Fund’s portfolio managers have day-to-day management responsibilities and the total assets in such accounts, within each of the following categories, as of September 30, 2025: registered investment companies, other pooled investment vehicles and other accounts. For each category, the number of accounts and total assets in the accounts where fees are based on performance is also indicated.

Name of PM		Type of Account		Number of Accounts Managed		Total Assets Managed		Number of Accounts Managed for which Advisory Fee is Performance Based		Assets Managed for which Advisory Fee is Performance- Based
Michael C. Buchanan‡		Other Registered Investment Companies		58		$85.01 billion		None		None
		Other Pooled Vehicles		194		$45.31 billion		16		$3.01 billion
		Other Accounts		285		$83.15 billion		12		$6.61 billion
Christopher F. Kilpatrick‡		Other Registered Investment Companies		11		$4.38 billion		None		None
		Other Pooled Vehicles		7		$564 million		3		$386 million
		Other Accounts		13		$860 million		None		None
Walter Kilcullen‡		Other Registered Investment Companies		8		$2.83 billion		None		None
		Other Pooled Vehicles		14		$6.53 billion		3		$386 million
		Other Accounts		11		$1.70 billion		None		None
John Hwang‡*		Other Registered Investment Companies		5		$2.20 billion		None		None
		Other Pooled Vehicles		9		$2.04 billion		6		$1.87 billion
		Other Accounts		2		$430 million		None		None
Ryan Kohan‡*		Other Registered Investment Companies		8		$3.12 billion		None		None
		Other Pooled Vehicles		22		$8.02 billion		9		$2.25 billion
		Other Accounts		13		$1.99 billion		None		None

‡ The numbers above reflect the overall number of portfolios managed by employees of Western Asset Management Company, LLC (“Western Asset”). They are involved in the management of all the Firm’s portfolios, but they are not solely responsible for particular portfolios. Western Asset’s investment discipline emphasizes a team approach that combines the efforts of groups of specialists working in different market sectors. They are responsible for overseeing implementation of Western Asset’s overall investment ideas and coordinating the work of the various sector teams. This structure ensures that client portfolios benefit from a consensus that draws on the expertise of all team members.

* Information for John Hwang and Ryan Kohan is as of March 31, 2026.

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The information contained in “Portfolio Manager Securities Ownership” in the “Portfolio Managers” section of the SAI is removed entirely and replaced as follows:

Portfolio Manager Securities Ownership

The portfolio managers held the following amounts of securities of the Fund as of September 30, 2025.

Portfolio Manager		Dollar Range of Securities Beneficially Owned ($)
Michael C. Buchanan		A
Christopher F. Kilpatrick		A
Walter Kilcullen		A
John Hwang*		A
Ryan Kohan*		A

* Information for John Hwang and Ryan Kohan is as of March 31, 2026.

Dollar Range ownership is as follows:

A: none

B: $1 - $10,000

C: 10,001 - $50,000

D: $50,001 - $100,000

E: $100,001 - $500,000

F: $500,001 - $1 million

G: over $1 million

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Portfolio Manager Updates Effective September 30, 2026

Effective as of September 30, 2026, the following supplements and, to the extent inconsistent with, supersedes the section entitled “Management of the Fund” in the Prospectus and the section entitled “Portfolio Managers” in the SAI:

Prospectus

The information relating to Christopher Kilpatrick is deleted in its entirety from the “Management of the Fund” section of the Prospectus

SAI

The information relating to Christopher Kilpatrick is deleted in its entirety from the “Portfolio Managers” section of the SAI.

Capitalized terms not defined herein have the meanings assigned to them in the Prospectus.

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