Investment Portfolio
Portfolio
Dashboard
Two accounts. A documented investment process, built in public.
About
I'm Isaac Toffel, an Economics and Data Science student at Northeastern University and a State Street co-op. This site documents how I think about portfolio construction, position sizing, and thesis-driven investing across my taxable brokerage and Roth IRA.
The goal is not to be right on every position. It is to build a repeatable process, track decisions honestly, and understand whether outcomes came from sound reasoning or luck. This site documents that process in public.
Education
Northeastern University
Experience
State Street
Certification
CFA Level I Candidate, Feb 2027 sitting
Isaac Toffel
Framework
Portfolio as a System
The portfolio is built as a system. Every position has a role, every account has a job, and sizing reflects conviction, time horizon, and how directly a name expresses the underlying thesis. The goal is not to own a large number of interesting companies. It is to concentrate capital where the upside is asymmetric and the construction makes sense at the total-book level.
The book is organized around two accounts. The Individual Brokerage holds ETF-based market exposure, semiconductor cyclicality, Bitcoin exposure, and select high-conviction equities. The Roth Retirement Account blends core market exposure with selective growth and measured speculative positions inside a tax-advantaged wrapper.
Position size is intentional. Larger weights are reserved for names closest to the center of the thesis. Smaller weights are used for emerging ideas or more speculative expressions where the upside may be meaningful but the path is less certain. A 10% position is not a stock I like more; it is a position that has earned a larger share of risk budget.
Diversification here is not just sector diversification. It is diversification by driver, maturity, and expression. Two AI-labeled companies can sit on very different parts of the value chain, with different customers, margin structures, and failure modes. What matters is not whether names look different on the surface, but whether they fail for the same reason.
The portfolio is meant to evolve. New positions have to earn their way in. Existing positions have to keep earning their size. I want the site to reflect not only what I own, but the logic that holds the portfolio together.
Discipline
Investment Policy
Position sizing
Core ETFs anchor the portfolio and can hold larger weights because they represent diversified market exposure. Individual equities are sized based on conviction, volatility, thesis maturity, and correlation with the rest of the portfolio. High-conviction individual equities generally target around 10% with a soft 11.5% upper bound unless the thesis is explicitly re-underwritten.
Account role
The Roth IRA is used for long-duration compounding, asymmetric growth, and tax-advantaged upside. The taxable brokerage account is used for flexible ETF exposure, thematic allocation, and liquidity. Account structure matters because the same holding can play a different role depending on tax treatment, time horizon, and rebalancing flexibility.
Trim / re-underwrite
A position moving above its target weight is not an automatic sell signal. It is a review signal. If the thesis has improved enough to justify the larger weight, the position can be re-underwritten. If price appreciation has outpaced thesis improvement, the position can be trimmed back toward target.
Sell discipline
Positions can be reduced or exited when the thesis breaks, valuation outruns evidence, a better opportunity emerges, or position size exceeds the intended risk budget. The goal is not to avoid volatility, but to make sure each position’s size still matches its evidence, upside, and downside risk.