Insider Trans

English terms

Insider Transactions, Insider Trading, Insider Trans%, Insider Buying/Selling

Korean terms

naebuja geolae, naebuja maemae donghyang, imwon jibun byeondong, naebuja sunmaesu/sunmaedo (net insider buying/selling)

Open Market Purchase — the strongest signal

This is when an insider directly buys their company's stock in the open market using their own money. Because the shares are bought with personal assets rather than received for free from the company, this is interpreted as the strongest positive signal. Open-market purchases by top executives such as the CEO or CFO are especially worth paying attention to.

Option Exercise — a weak signal

Stock options are granted as part of compensation, and because the exercise price is below the current market price, exercising them is simply a rational economic decision. So option exercises can be seen as routine transactions with little meaning. However, it is important to distinguish between "Exercise and Sell" (selling immediately after exercising) and "Exercise and Hold" (keeping the shares after exercising).

Open Market Sale — context matters

Insiders sell shares for many reasons. Most have nothing to do with the company, such as diversifying assets, paying taxes, or needing personal funds. However, caution is needed when multiple insiders sell large amounts at the same time or right before an earnings release.

Automatic Sales Under a Rule 10b5-1 Plan — a neutral signal

An SEC Rule 10b5-1 Plan is a pre-arranged trading plan that lets insiders automatically buy or sell shares according to a preset schedule and conditions. Many executives set up these plans to avoid suspicion of trading on inside information. Because sales under such plans are regular and predictable, they are generally not interpreted as a negative signal. Form 4 will indicate "10b5-1" when applicable.

Insider Trans +10% or higher — a very strong buying signal

This means insiders increased their holdings by more than 10% over the last 6 months. It is an even stronger signal if multiple insiders are buying at the same time. This is called cluster buying, and academic research shows that stocks with cluster buying tend to deliver above-average returns within 6 to 12 months.

Insider Trans +1% to +10% — a positive signal

This means insiders are making small additional purchases. It is a positive signal showing confidence in the company, but you should also check the purchase amount and the rank of the buyer. A CEO buying $1 million is not the same as a director buying $10,000.

Insider Trans around 0% or no transactions — neutral

This means there have been no recent insider transactions, or buys and sells roughly offset each other so there is little net change. On its own, this does not tell you anything positive or negative. Insider transactions can be rare in large-cap stocks.

Insider Trans -1% to -10% — caution needed

Insiders are making small sales. Most of these are for personal reasons such as diversifying assets or paying taxes, but you should still check the timing and pattern. If the sales are routine under a Rule 10b5-1 plan, there is little cause for concern.

Insider Trans -10% or lower — a warning signal

This means insiders have sold more than 10% of their holdings, so caution is needed. Cluster selling, where several insiders sell large amounts at the same time, is a strong warning signal. However, there can also be structural reasons such as post-IPO lock-up expirations or stock option maturities, so you should always check the context.

Insider Trans vs. Insider Own

Insider Own is the current insider ownership percentage (a snapshot), while Insider Trans is the recent trading activity (a video). Looking at both together gives you a much more three-dimensional analysis. For example, if Insider Own is 15% and Insider Trans is +5%, that is a very positive signal meaning "insiders already hold a large stake and are buying more." On the other hand, if Insider Own is 30% and Insider Trans is -20%, that is a warning signal meaning "major shareholders are selling heavily."

Insider Trans vs. Inst Trans (Institutional Transactions)

Inst Trans tracks buying and selling by institutional investors (mutual funds, hedge funds, etc.). Insider transactions are based on inside knowledge of the company, while institutional transactions are based on outside analysis. If insider buying and institutional buying happen at the same time (positive Insider Trans + positive Inst Trans), that is a very strong signal that both insiders and outsiders are positive on the company. If the two diverge (insiders buying while institutions sell), further analysis is needed.

Insider Trans vs. Short Float (Short Interest)

It is an interesting situation when insiders are buying while short interest is high. Insiders have confidence in the company's future and are buying, while some outside investors are betting the stock will fall. If the insiders turn out to be right, a short squeeze could occur and the stock could jump sharply.

This situation... CEO makes a large open-market purchase after a sharp stock drop

One of the strongest positive signals is when a CEO uses their own money to buy a large amount of company stock after the price has plunged on bad news. It is essentially the CEO saying, "the market has overreacted." In 2022, JPMorgan CEO Jamie Dimon bought about $26 million worth of his company's stock when the price was falling, and the stock later rebounded strongly. However, a CEO's purchase is not always right, so you should still analyze the company's fundamentals.

This situation... Multiple insiders buying at the same time (cluster buying)

Several insiders buying at the same time is a much stronger signal than just one insider buying. If the CEO, CFO, and three or four directors all buy shares around the same period, it means the entire leadership team believes the current stock price is undervalued. Academic research shows that stocks with cluster buying tend to outperform the market over the next 12 months.

This situation... Insider transactions right before or right after earnings releases

Most companies set blackout periods that ban insider trading around earnings releases, usually from 2 to 4 weeks before the release until 2 days after. If insiders start buying right after the blackout period ends, that is a strong signal that they are satisfied with the just-released earnings and confident about the outlook. On the other hand, if large sales occur immediately after the blackout ends, that is a warning sign.

This situation... Screening that combines insider transactions with valuation

In the Finviz screener, you can filter for stocks with a positive Insider Trans (net buying) and a Forward P/E below the industry average to find stocks where insiders are buying in undervalued territory. Adding a positive Inst Trans (institutional net buying) as another filter gives you an even more reliable candidate list.

This situation... Insider activity around the post-IPO lock-up expiration

After an IPO, there is usually a lock-up period of 90 to 180 days, after which insiders can sell their shares for the first time. Many investors worry about heavy selling at this point. But if insiders do not sell — or even buy more — after the lock-up expires, that is a very strong positive signal. It means their confidence in the company's future is that high.

Technology

Stock options and RSU compensation are very common in tech, so insiders routinely sell shares (after exercising options). For this reason, insider selling in tech stocks should not be treated as an immediate warning. The key is to distinguish open-market purchases from option-exercise sales. Open-market purchases by tech CEOs are rare, so when they occur they are an especially strong signal.

Financials

Stock purchases by bank CEOs attract particular attention, because bank executives have deep insight into loan quality, the interest rate environment, and regulatory changes. During the 2008 financial crisis, some bank CEOs who bought large amounts of their own stock were essentially saying the market's fear was excessive, and they ended up making significant gains.

Biotech

Insider purchases in biotech carry special meaning. The results of a drug's clinical trial can change a company's value by several times to several tens of times. If insiders buy before a major clinical result is announced, it may reflect expectations of a positive outcome (though trading on inside information is illegal). In biotech, insider-transaction signals are an especially powerful source of alpha (excess return).

Energy

Insider transactions in the energy sector are closely tied to oil and gas price outlooks. Energy executives have a high level of understanding of global supply and demand, OPEC policy, and geopolitical risks. If insiders start buying when oil prices have plunged, that can be interpreted as confidence in an oil-price rebound.

1. Distinguish between legal and illegal insider trading

When you hear the words "insider trading," it is easy to think of something illegal, but insider stock trades that are reported and disclosed to the SEC are perfectly legal. Illegal insider trading refers to using material non-public information (MNPI) to gain profit or avoid loss. The Insider Trans discussed in this article refers to legal transactions disclosed to the SEC.

2. Understand the asymmetry between buys and sells

Insider buying and selling carry very different signal strengths. Buying almost always means just one thing (an expectation that the price will rise), but selling can happen for many reasons. Most insider selling has nothing to do with the company's prospects: portfolio diversification, paying taxes, kids' tuition, buying a home, divorce settlement, charitable giving, stock option expiration, and so on. So it is wise not to overreact to insider selling and to put more weight on buying signals.

3. Check the buyer's position and the amount

Even when it is an insider purchase, the meaning depends heavily on who is buying and how much. A CEO investing $5 million carries a very different signal strength from an outside director investing $10,000. Top executives like the CEO and CFO have the most information about the company, so their trades deserve more weight. The signal is even stronger when the purchase amount is a meaningful share of the person's annual salary.

4. Do not make investment decisions based on Insider Trans alone

Insider transactions are only one input into an investment decision. No matter how much insiders are buying, the stock may still be a bad investment if the company's fundamentals are weak, the valuation is excessive, or the industry outlook is poor. Insiders can be wrong too. Always review financials, valuation, and industry trends together before deciding to invest.

5. Be aware of the time lag

Form 4 must be filed within two business days after the trade, but analyzing it and incorporating it into investment decisions takes additional time. The price at which an insider bought may have already moved significantly compared to the current price. There is also a delay before sites like Finviz reflect the data, so the fastest information can be obtained by going directly to SEC EDGAR.

Differences between Korean and U.S. insider-disclosure systems

In Korea, you can check insider transactions through the Financial Supervisory Service's electronic disclosure system (DART) using the "Executive/Major Shareholder Holdings Report." This is similar to the U.S. SEC's Form 4, but the U.S. has a shorter reporting deadline (2 business days) compared to Korea (5 business days), and data accessibility and analytical tools are also more developed. SEC EDGAR is in English, but sites like OpenInsider make it easy to grasp the information even if you are not comfortable in English.

An investment strategy that takes advantage of the time difference

Form 4 information is disclosed after the U.S. market closes (around 6:00 a.m. Korean time), and you can analyze it before the next U.S. market opens (before 11:30 p.m. Korean time). If a large insider purchase is disclosed after the U.S. market close, you can analyze the company during Korean daytime hours and decide whether to buy when the U.S. market opens. Pre-market orders are available through Korean brokers such as Kiwoom Securities and Mirae Asset Securities.

Taxes and exchange-rate considerations

When Korean investors follow insider-buying signals into U.S. stocks, they must consider capital gains tax (22% on gains exceeding KRW 2.5 million) and exchange-rate movements. If you plan to hold for 6 to 12 months after an insider purchase, calculate in advance the expected taxes and possible FX losses on those expected gains. Making good use of the annual KRW 2.5 million capital-gains tax exemption can reduce your tax burden.

Korean-language services that provide insider-transaction information

Korean brokerage apps do provide some insider-transaction information, but the data is often limited and updates are slow. If you want more accurate and faster information, it is recommended to check OpenInsider (openinsider.com) or SEC EDGAR directly. Using the Chrome browser's translation function, English-language sites can be read comfortably in Korean. USStockToday also provides insider-transaction information by stock in Korean, so feel free to use it.