Equity Research: Inside the Portfolio

Quick Answer

What is Inside the Portfolio?

It is Sirmium Capital's quarterly equity research letter, written by our Chief Investment Officer, William Harrison. Each issue lays out how we read the market, how the portfolio is positioned, and the reasoning behind a specific holding, in plain English. Past issues are free to download below, and you can subscribe to get each new one. This is educational research, not personalized investment advice.

The Letter

Research written for long-term investors

Concentrated value investing

How we find durable businesses trading below intrinsic value, and why we hold a focused portfolio instead of a diluted one.

Written for years, not quarters

Portfolio strategy and capital allocation framed for investors who measure results over market cycles, not headlines.

Free, every quarter

One issue per quarter, timed to our portfolio review. Free to read, free to subscribe, no spam, unsubscribe anytime.

Written By

William Harrison

Founder & Chief Investment Officer

William leads Sirmium Capital's investment process, portfolio construction, and capital allocation. He writes every issue of Inside the Portfolio himself, so what you read is the same thinking that drives the firm's decisions, not a marketing summary of it.

The approach is concentrated value investing: buy durable, well-run businesses when the price is well below what they are worth, and hold them long enough for that to matter.

View our adviser record (IAPD) More about the firm

Latest Issue

Q2 2026: The Founders Knew This Was Coming

Issue 06 · Q2 2026 In Review

The Hamilton versus Jefferson fight over national debt, and what roughly 39 trillion dollars of it, with about a trillion a year in interest, means for how a portfolio should be built from here. Plus the quarter's portfolio update and a stock recommendation.

Listen to this issue · 20 min

Read the Q2 issue (PDF)

Get the next issue by email. Subscribe free.

Sirmium Capital LLC is a registered investment adviser. Educational purposes only, not individualized investment advice. Past performance does not guarantee future results.

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Past issues

Issue 05 · Q1 2026

Fear, Headlines, and Opportunity

Why markets fall on uncertainty, not deterioration, and where the gap between price and reality creates opportunity. Market outlook, portfolio update, and a stock recommendation.

Listen · 23 min

Download (PDF)

Issue 04 · 2025 Year in Review

Is This Time Really Different?

Reading the AI-bubble question through the lens of market cycles and circular capital flows, plus a full-year portfolio review and recent additions.

Listen · 22 min

Download (PDF)

Get the next issue by email. Subscribe free.

Questions

About the Research Letter

William Harrison, Sirmium Capital's Founder and Chief Investment Officer, writes every issue of Inside the Portfolio. It reflects his personal investment research and the thinking that drives Sirmium Capital's portfolio decisions.

Inside the Portfolio is published quarterly, four times per year. You will receive one issue per quarter, timed to coincide with William's portfolio review process.

Every published issue is in the archive on this page, free to download as a PDF. A new issue is added each quarter, each issue has a free audio overview, and subscribers get each one by email as it is released.

No. Inside the Portfolio is an informational research letter for educational purposes only. It does not constitute investment advice, a solicitation, or an offer to buy or sell any security. Your individual circumstances require personalized advice. Please consult a qualified financial adviser.

Yes. Past issues are free to download and the newsletter is free to subscribe to. Sirmium Capital provides it as a service to our clients and to the communities we serve. There is no charge, and you can unsubscribe at any time.

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