William Harrison's quarterly equity research letter. Concentrated value investing analysis, portfolio strategy, and long-term capital allocation, written for investors who think in years, not quarters.
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
How we find durable businesses trading below intrinsic value, and why we hold a focused portfolio instead of a diluted one.
Portfolio strategy and capital allocation framed for investors who measure results over market cycles, not headlines.
One issue per quarter, timed to our portfolio review. Free to read, free to subscribe, no spam, unsubscribe anytime.
Written By
Co-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.
Latest Issue
Issue 07 · Q3 2026 · October 8, 2026
Bill Miller's three sources of investing edge, and which ones AI wears away. How narrow the market's gains have become, how the largest cloud companies are paying for the AI buildout, and the quarter's portfolio changes.
Read the Q3 issueGet the next issue by email. Subscribe free.
Sirmium Capital LLC is a New York state-registered investment adviser and is not registered with the SEC. Educational purposes only, not individualized investment advice. Past performance does not guarantee future results.
Market Commentary
September 2026 · New York City
What the city's largest-ever budget was actually closed with, and what a deficit bridged by one-time and borrowed sources means for capital deployed in and around New York. Numbers first, no political scorecard.
Read the commentaryNYPD member? Read The City Stretched Its Pension Debt to 2037. Your Fund Said No.
Sirmium Capital LLC is a New York state-registered investment adviser and is not registered with the SEC. Educational purposes only, not individualized investment advice. Past performance does not guarantee future results.
Subscribe
Market outlook, portfolio update, and one researched stock idea, four times a year. Free, no spam, unsubscribe anytime.
Now in its seventh issue.
You're in. The next issue will land in your inbox.
Read Will's latest research letter →
Something went wrong. Please try again.
Prefer a reader? Subscribe via RSS
Archive
Issue 06 · Q2 2026
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.
Download (PDF)Issue 05 · Q1 2026
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.
Download (PDF)Issue 04 · 2025 Year in Review
Reading the AI-bubble question through the lens of market cycles and circular capital flows, plus a full-year portfolio review and recent additions.
Download (PDF)Questions
Go Deeper
Questions about your portfolio?
Book a free 15-minute call to ask about the research, our approach, or your own situation. Straight answers, no follow-up pressure.
Book a Free 15-Min Call
Quarterly equity research from CIO William Harrison. Free, no spam.
Informational only. Sirmium Capital LLC is a New York state-registered investment adviser and is not registered with the SEC.