I built InsiderSignals because the most useful dataset I ever found as a self-directed investor, insider buying data that has historically beaten the market, was unusable in its raw form and unknown to almost every European investor I talked to. This is the story of how an insider trading tool for European investors went from a personal frustration to a live product.

I started investing in US stocks the way most European investors do, through a brokerage app. DEGIRO made it easy: a few taps and I owned shares in companies listed on the NYSE and Nasdaq, sitting in my apartment in Amsterdam. Getting access was the easy part; knowing which stocks to buy was not.

I tried the usual approaches. Fundamental analysis took hours per company and I still wasn't confident. Following influencer picks felt irresponsible. Screening tools returned hundreds of results with no way to prioritize. I wanted a systematic starting point, something grounded in data rather than opinions. Then I stumbled onto SEC Form 4 filings.

The discovery

In the US, every director, officer, and major shareholder of a public company must file a report called a Form 4 with the SEC within two business days of buying or selling their own company's stock. These filings have been required since 1934, and they're public: anyone can access them.

When I first saw one, two things struck me. First, this was an enormous dataset: millions of filings spanning decades, covering every publicly traded company in the US. Second, almost nobody in Europe knew it existed.

As a European investor with an economics background, I'd never encountered this data in any of the investing resources I used. In the Netherlands, and across most of Europe, "insider trading" means the illegal kind. Executive stock trading here is tightly controlled through compliance officers, pre-clearance requirements, and mandatory closed periods. The idea that US executives trade openly and report publicly was genuinely new to me.

The problem with raw data

Having access to insider filing data and being able to use it effectively are two very different things.

SEC EDGAR publishes thousands of Form 4 filings every week. Open them up and you'll find stock grants, options exercises, automatic selling plans, and tax withholdings: transactions that happen on autopilot regardless of what the executive thinks about their company's prospects. About 85% of all filings fall into this category. Only about 15% are discretionary open-market purchases, where an executive chooses to write a personal check and buy shares. That minority of filings is where the signal lives; the rest is noise.

Existing tools, like OpenInsider, show you everything: every filing, unscored, unranked, with no indication of which ones might actually matter. It's like drinking from a fire hose.

The idea

The product I wanted was a scoring layer: a system that looks at who bought, how much they spent, what percentage of their holdings it represented, and how similar trades had performed historically, then surfaces only the ones that actually matter.

It wouldn't be a stock-picking service or a recommendation engine, just a data-driven filter that separates signal from noise in one of the richest public datasets in finance.

The build

I started processing the data: over 4 million SEC filings spanning 2015–2026, covering every open-market equity purchase with its full context (insider role, trade size, holding changes, filing dates, and price history).

I trained a logistic regression model on historical outcomes, looking at which insider purchases were followed by significant positive returns and what characteristics distinguished them from the rest. The model evaluates 3 compound factors for every trade: insider quality, market context, and transaction strength.

The result is a scoring system that assigns every insider purchase to one of five tiers: Elite, Strong, Positive, Neutral, and Caution. The top tiers represent the trades where the insider's profile, trade characteristics, and historical patterns all align, the small subset of filings where the data says "pay attention."

Everything is designed to be verifiable: every score shows a breakdown across all 3 factors, every filing links to the original SEC source, and nothing is hidden behind a black box.

The gap

The more I built, the more convinced I became that this tool needed to exist specifically for European investors.

Every competitor in the insider data space is US-centric: the messaging assumes you know what a Form 4 is, the products assume you're checking between market hours in New York, and the content assumes you've been following finance Twitter for years.

None of them address the fact that most European retail investors (people using DEGIRO, Interactive Brokers, Trading 212, Saxo) have the same market access as American investors but almost none of the data tools. And none of them address the fundamental misconception that insider trading is always illegal.

That's the gap InsiderSignals fills: not just the scoring and filtering (though that matters), but the education layer that makes this data accessible to investors who've never encountered it before.

Where it stands

InsiderSignals is live. The model processes new filings within 15 minutes of SEC publication, the dashboard shows every scored trade with full transparency, and email alerts notify users of high-conviction signals in real time.

In a decade-long backtest, high-conviction signals returned over 7× the S&P 500. But a backtest is a starting point, not a promise. The real value is in what happens next: giving self-directed investors a systematic, evidence-based input to their research process.

I built this because I wanted it for myself. I keep building it because the data keeps being interesting.

Try it free for 30 days at insidersignals.io.

Related Reading

• Not All Insiders Are Equal: Which Roles Produce the Strongest Signals: The role-level analysis behind the insider quality factor in the scoring model.
• WSJ Analyzed 1,400 Insider Buys. Here's What They Missed.: Why unfiltered studies of insider buying find weaker results than scored ones.
• The Timing Edge: Why Speed Matters in Insider Trading Signals: What the filing-to-alert window means for acting on insider signals.

For informational purposes only. Not investment advice.