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Who we are, what we publish, and why you should trust any of it.
Who We Are
We’re a father and son.
Don Copley spent forty years as a cardiologist, a solo practitioner who trusted evidence over anecdote and lived by first, do no harm. Along the way, he also became a lifelong index-fund investor, and for years he ran his own momentum strategy out of an Excel spreadsheet he refined almost every day. His goal wasn’t to get rich quick; in his words, it was to “eliminate emotion-based investment decisions” and “sleep soundly at night.”
I’m Devon Copley, his son. I’m a programmer and technology entrepreneur, and for a long time, a skeptic. I believe in efficient markets, and I didn’t see how my old man’s ancient spreadsheet technology could beat the S&P. But year after year, it did just that. So I did what an engineer does: I pointed modern backtesting and a lot of computing horsepower at the strategy to prove my dad wrong.
The strategy wouldn’t break. The harder I tested it, across full market cycles, with real trading costs modeled, through the crisis years, the better it held up. I set out to debunk and wound up validating. And then I started picking the strategy apart and improving it, bit by bit, backtest by backtest.
This newsletter is the result of both of our work.
What This Substack Is About
We publish a small set of model portfolios built on the two research-backed ideas my dad combined: trend-following and low-cost index funds. Trading just once a month, the strategy aims to beat buy-and-hold over the full market cycle, with far shallower drawdowns in bear markets (backtested since 2006; hypothetical, not indicative of future results). Note that this strategy trades frequently so it would be subject to short-term capital gains in a taxable account; it is designed for use in tax advantaged accounts only (IRA, 429, 401k, etc).
The headline numbers since 2006:
CAGR (Annualized Return) of 20.9% (vs. the S&P 500 at 11.0%)
Worst 12 months of -5.3% (vs S&P at -47.4%)
Every month we publish the models and the exact trade signals. You place the trades yourself, commission-free, in the tax-advantaged account you already hold: an IRA, Roth, or 401(k). We never touch your money. We’re publishers, not managers.
No day trading. No long-short hedging. No AI gimmicks or hot takes. Just a handful of transparent rules, run the same way every month.
Who It Is For
People who already believe in index funds but are tired of the two bad choices: ride every crash to the bottom, or hand a chunk of their returns to an advisor to avoid it. If you’d rather run a simple, rules-based system yourself (and keep the keys to your own account), this is for you.
It’s built for a tax-advantaged account (IRA / Roth / 401k). Because the strategy reallocates monthly, it realizes mostly short-term gains, costless inside a tax-sheltered account, but a real drag in a taxable one that we don’t model and won’t paper over. Run it where it’s meant to run.
What We Believe
Markets are efficient. We don’t chase hot tips or esoteric theories. The price contains the information; that’s the input to our system.
Simple beats clever. A handful of explainable rules beats an elegant machine with a hundred dials. Every extra knob is just another way to fool yourself.
Index funds beat stock pickers. Over every time frame that matters, low-cost index funds beat the vast majority of active managers. We don’t think we can pick stocks, and we don’t pretend we can pick the pickers either.
Momentum is the proven edge. Dozens of studies covering across centuries of markets agree: the crowd buys winners and sells losers a little bit more than they should. Harvested diligently, the trend is your friend.
(These four are the short version. If you want the full set of eight, with the research behind each one, check out our Credo, linked below.)
Why You Should Trust Us
We show our work: what we tried, what we kept, and what we threw out, and why. We publish the losing months alongside the winners, model realistic trading costs, and state the limitations out loud, including the ones a backtest can never resolve on its own. A backtest can’t fully prove itself; the live, public record (committed in advance, timestamped, and building from day one) is the proof we actually stake the brand on.
And the strongest signal we can offer: we invest our own money the same way. I run it in my own retirement account as he saves; my mom and dad live off theirs. We’re our own first customers.
Where to Go Next
Two things, in order, if you want the rest of the story:
→ Read our full credo: the eight beliefs behind every rule we run, with the research behind each one.
→ How it works: This post walks through the method and the results.
Or skip straight to the numbers: → See the models and the actual track record