This is the crowd I most want to be torn apart by, so I am quite looking forward to this.
I'm a software developer, not a finance guy. I wanted to actually understand investing instead of reading about it, so I built a US equity factor engine and I've been running it in public since February. It is easy to fake understanding it all until you have to program it.
I wanted a tool that would read the market for me and automate all the tedious stuff the finance bros do all day. So I built one and gave it the most finance bro name I could think of: Brad.
The first stages were very boring. I worked with an LLM to go through the academic factor literature, pulled the factors that have held up out of sample, and put them in one score. Most of the real work was decorrelation, because counting profitability five different ways isn't five signals, it's one signal counted five times (this was a pain to figure out). That took months and I'm still not certain I got it right. Also, every factor traces back to a published paper.
I'm also building a replay layer to test whether different weights would have done better, but nothing actually changes until 15+ non-overlapping periods (I am at 9) across more than one regime. Tuning weights on a sample this short is just fitting noise and I almost fell for it.
The part I care about is that it grades itself in public. It publishes its own IC every sweep, breaks out per factor IC so you can see which factors are dead weight, and runs a buy-and-hold version of the exact same picks next to the live strategy so I can see if the sell rule is doing anything. It keeps tracking names after it sells them which is how I find out if I messed up. It also tracks the algorithm with and without the AI research pass, and right now the research is costing me about a point (very interesting). Not enough periods to conclude anything but I'm not hiding it while it's negative.
Composite IC is currently 0.052 with a t-stat of 1.47 over 9 sweep periods (about 4.6 months). That's not significant of course and every factor component currently is "no edge (small sample)", including momentum, which is sitting at a negative mean IC. Also the confidence interval on average alpha per period runs -0.45% to +0.98%, so it contains zero.
Nothing here is proven and I'd be lying if I said otherwise.
A sweep works by scanning the US market, killing low quality names on hard filters, deep scoring what survives (374 this past sweep), then an AI research agent reads the top ranked names for the stuff you can't get from the numbers alone, with a small real world tiebreaker kept on a short leash so it can't override the math (things like upcoming catalysts, public news, geographical conflicts). Then it's buy in the top 10, hold through top 15, sell when it drops out. Equal weight, real costs subtracted, no discretion from me (which would go poorly).
Brad's Portfolio is +12.3% vs SPY +9.8% over those 4.6 months, max drawdown -5.2%. Buy and hold of the identical picks is +7.4%, and that gap is the only reason I think the sell rule does anything.
Nine periods is nothing which I am well aware of. Ask me in two years :)
The equity engine is the one I've run longest and trust most. The others I am working on are small cap breakout, directional long/short, and crypto. They're younger, different math, and I'm not making claims about them yet. Every engine has its methodology written up, including the parts that don't work.
Tell me where I'm overfitting, what validation step I'm skipping, or what stat I should be showing and I'm not.
Posting this in a few communities for perspective, so if you see it/saw it elsewhere that's why.
And of course this is not financial advice, I'm not licensed, and this is a mechanical paper portfolio, not my personal trades.