Shibui Finance gives Claude access to 6.4 million parsed insider transactions from SEC Forms 3, 4, and 5 covering nearly 10,000 NYSE and NASDAQ companies. Each transaction includes the shares traded, price per share, transaction code (purchase, sale, award, exercise, gift), the insider's name and role (officer, director, or 10%+ holder), and whether the trade was part of a pre-arranged 10b5-1 plan. You can screen for insider buying across the entire market, track individuals across all their positions, detect cluster buying (multiple insiders at the same company), and measure whether insiders were right by checking subsequent price moves. Free, no API key, no subscription.
To screen the whole market for insider buying combined with valuation and technical criteria, see the Insider Buying Stocks screener page.
What Forms 3, 4, and 5 reveal
Every officer, director, and 10%+ shareholder of a public company must disclose their trades to the SEC. Form 4 is the workhorse - it reports every purchase, sale, option exercise, and gift, and must be filed within two business days of the transaction. Form 3 is the initial ownership statement filed when someone first becomes an insider. Form 5 is an annual catch-all for any transactions that were not reported on Form 4 during the year.
Shibui parses these filings into structured transaction records. Each record includes the transaction date, the number of shares, the price per share, the transaction code, the insider's identity and role, and a flag indicating whether the filing was later amended (superseded). This is not just metadata - it is the actual transaction detail extracted from the XML filings.
Detect cluster buying
A single insider purchase might be noise - an executive exercising options or following a scheduled 10b5-1 plan. Multiple insiders buying at the same company in the same month is a stronger signal. Cluster buying detection scans Form 4 filings across the entire market to find companies where several insiders purchased shares within a short window.
"Show me companies where 3 or more insiders filed Form 4 open-market purchases in the last 30 days. Include the company name, number of insider buyers, total shares purchased, and current market cap. Sort by market cap."
Claude filters to transaction code P (open-market purchase), excludes derivative transactions and superseded filings, and groups by company. The result is a list of companies with meaningful insider conviction, ranked by size.
Net insider buy/sell value
Beyond counting filings, you can measure the dollar value of insider activity at any company. This aggregates the total value of insider purchases minus sales over a given period, giving you a net conviction signal.
"What is the net insider buy/sell value for AAPL in the last 12 months? Show total purchases, total sales, and net value. Only count open-market transactions on common stock."
Were the insiders right?
The most interesting question about insider trades is not just what they bought, but whether buying was a good signal. By joining insider transaction dates with subsequent price data, you can measure whether insider purchases preceded positive returns.
"For large-cap stocks where insiders made open-market purchases in Q1 2026, what was the average stock price change 30, 60, and 90 days after the purchase date? Compare to stocks where insiders sold."
This is an event study over insider transactions. Claude joins each transaction date with the stock's price at fixed forward offsets and aggregates the results. The database has daily prices back to 1962 for this kind of cross-referencing.
Track an individual across all companies
The insider_entities table resolves each insider's identity across all their filings. If someone sits on multiple boards or manages multiple positions, you can track their complete trading history in one query.
"Show me all Form 4 filings by Jensen Huang. Include each transaction date, company, shares, price, and whether it was a purchase, sale, or exercise."
Transaction codes explained
| Code | Meaning | Signal value |
|---|---|---|
| P | Open-market purchase | Strongest buy signal - insider spent their own money |
| S | Open-market sale | May signal concern, but also routine diversification |
| A | Award/grant | Compensation event, not a market signal |
| M | Option exercise | Often followed by S (exercise-and-sell); alone, neutral |
| G | Gift | Tax planning or philanthropy, not a market signal |
| F | Tax withholding | Automatic share surrender for taxes, not a sell signal |
| J | Other acquisition | Various non-market transfers |
| C | Conversion | Security conversion, not a market transaction |
When screening for insider sentiment, filter to codes P and S. Awards (A), exercises (M), and tax withholdings (F) are routine compensation events that dilute the signal if included.
10b5-1 pre-arranged plans
A 10b5-1 plan is a pre-arranged trading schedule that insiders set up in advance to avoid accusations of trading on material non-public information. Transactions under a 10b5-1 plan are flagged in the data. These are less informative as buy/sell signals because the trade was scheduled weeks or months before execution, but they are still useful for tracking the volume and direction of planned insider activity.
Data quality notes
Amended filings: About 2.3% of insider filings are later amended. Shibui automatically excludes superseded filings so you do not double-count transactions.
Derivative vs common: Insider filings cover both common stock and derivative securities (options, warrants, convertible notes). When you ask about share counts or dollar values, Claude filters to common stock transactions since derivatives trade at different scales.
Fat-finger detection: A small fraction (~0.04%) of priced transactions have extreme values from data entry errors. Claude flags these by checking whether the implied transaction value exceeds the company's market cap on that date.
Questions
Is there a free insider trading screener?
Shibui Finance is a free insider trading screener that connects to Claude. It gives Claude access to 6.4 million parsed Form 3, 4, and 5 filings with full transaction detail: shares traded, price per share, transaction codes, officer titles, and 10b5-1 flags. You can screen for insider buying across the entire US market. No API key, no subscription.
How do I track insider stock purchases?
Connect Shibui Finance to Claude and ask in plain English. For example: "Show me companies where three or more insiders purchased shares in the last 30 days." Claude queries the insider_transactions table with parsed Form 4 filings including transaction dates, share counts, prices, and the identity of each insider.
Can I track what a specific CEO is buying?
Yes. The insider_entities table resolves insider identities across all their filings. Ask Claude "Show me all Form 4 filings by Jensen Huang" and it returns every transaction across all companies where that person is an officer, director, or 10%+ holder.
What is the difference between Form 3, Form 4, and Form 5?
Form 3 is an initial ownership statement. Form 4 reports changes in ownership (purchases, sales, exercises, gifts) and must be filed within two business days. Form 5 is an annual summary. Form 4 is the most common and most useful for tracking insider buying and selling.
What SEC insider trading data does Shibui Finance have?
6.4 million parsed transactions from Forms 3, 4, and 5 covering nearly 10,000 NYSE and NASDAQ companies. Each record includes filing date, transaction date, shares, price per share, transaction code, insider identity and role, 10b5-1 flag, and amendment status. The data also flags known activist investors.
Related SEC filing pages:
- SEC Filings Hub — overview of all filing types and data coverage
- Insider Buying Stocks — market-wide screen for Form 4 purchases
- 13D and 13G Filings — activist investors and major holders above 5%
- Track Filing Activity — triage the daily 8-K feed by market cap