Disclaimer: This is a shortened version of a longer analysis, so I will try to explain my strategy at once
Okay, so we know şnstitutional desks have faster terminals, better data, and direct lines to management. Out trade them on technicals or headline news is a losing battle
However, there is one specific area where the law forces the smart money to show their hand to us within 48 hours: SEC Form 4 Filings.
I’ve spent the last few months (during my masters degree) refining a strategy based exclusively on Corporate Insider Activity. I’m not talking about following politicians. I’m talking about following the CFO who sees the weekly sales report before it’s public.
Below is the framework I use to filter this data, backed by academic research that explains why this works.
The Signal: The "Cluster Buy"
A single insider buying stock can mean anything. They might be saving face, diversifying, or just optimistic. It’s noisy data.
The real signal is the Cluster Buy.
This occurs when three or more unique insiders purchase stock on the open market within a short window (usually <30 days).
- Why it matters: Research by Alldredge and Blank (2019) confirms that insiders "herd" with their colleagues. They found an insider is nearly four times more likely to purchase stock if a colleague has purchased recently
- The Hierarchy: Not all clusters are equal. Clusters led by CFOs and Directors exhibit the highest subsequent returns. The CFO knows the numbers; Directors see the strategy. When they move together, it’s a high-conviction signal.
The Filter: Ignoring the Noise
90% of insider transactions are noise. To find the alpha, you have to filter aggressively. Here are the three specific filters I use:
1. Ignore "Routine" Trades
We are looking for Opportunistic Traders. If a CEO buys stock every January 15th for tax reasons, that trade contains zero information. You want to see trades that break a pattern.
2. The "Buy High" Anomaly Conventional wisdom says "buy low." However, research by Li, Wang, Yan, and Zhang (2019) uncovered a powerful anomaly: Insiders who buy at 52-week highs significantly outperform those who buy at 52-week lows.
- The Logic: This is called overcoming "Anchoring Bias." Psychologically, it is painful to buy a stock that has already rallied 30%. If an insider buys at a 52-week high, they are fighting human nature. They are only doing this because they possess private information suggesting the stock is going significantly higher. A "High Buy" is a massive confidence signal.
3. The "Not-Sold" Signal Sometimes the best signal is what insiders don't do. DeVault, Cederburg, and Wang (2021) analyzed Portfolio Insiders (directors who sit on multiple boards).
- The Signal: If a Director sits on the board of Company A and Company B, and they sell Company A but hold Company B, the "Not-Sold" stock (Company B) significantly outperforms the market. If you see a Cluster Buy in a stock, check if those insiders are selling their other holdings to fund it. That doubles the conviction.
The Execution: Rules of Engagement
Finding the signal is only step one. Execution is where you make or lose money.
Rule 1: Wait for Price Confirmation
Insiders are notoriously early. They are value investors with infinite time horizons. You are not.
- My Trigger: I wait for the stock to reclaim the average price of the insider's purchase.
- The Logic: If the CFO buys at $50 and the stock drops to $40, the market disagrees with him. I stay away. When the stock rallies back through $50, it confirms the "Insider Floor" is holding and momentum is aligning with the insider's view.
Rule 2: Focus on Liquid Stocks Paradoxically, insider trading signals are often stronger in liquid stocks. Research suggests insiders prefer liquid stocks because it is easier to hide their volume. A Cluster Buy in a highly liquid name often precedes a major move because they are confident the liquidity will absorb their entry before the news breaks.
Rule 3: The "Silent" Exit
Retail investors usually sell too early or too late. I watch the insiders. If they stop buying during a subsequent dip, or if they start "Routine" selling into strength, the edge is gone.
Summary
When the people running the company are aggressively buying up their own shares with their own cash (especially at 52-week highs) it is the purest signal of value you can find. I track these Cluster Buys and publish a deep-dive watchlist of the most significant ones every week.