Insider transaction refers to any trading activity that involves a person or organization with access to valuable information about a company. This can include anyone who has direct access to company financial results, as well as corporate insiders (those with substantial knowledge about the company’s operations) and investors, who may have privileged access to information through positions in the stock market.

Insider trading can be classified into two types: legal and illegal. In general, it's legal to buy and sell your own shares if they're registered with the Securities and Exchange Commission (SEC) and you meet certain requirements. If a trader interferes with the market by acting on this information in an attempt to profit on it, however, they could be breaking securities laws. For example, insider trading is illegal if you are working for a competitor or have non-public information about another company that could be used to make a profit by buying or selling its stock. Other possible violations include disclosure failures.
One of the most common forms of insider trading is when an investor trades shares in a company that they own or are otherwise privy to confidential information about. This can be done for a variety of reasons, including personal greed, wanting to sell before others realize the value of the stock, and simply being careless. While illegal, instances of insider trading are not nearly as rare as one might assume - in fact, it’s quite common and can occur in any industry or situation where money is involved.

In general, insider buying is considered a positive event by investors. When a director or executive at a company buys shares in their own company, it is seen as an indication that the executive believes in the long-term prospects of the company and has confidence that the share price will continue to rise. Furthermore, if insiders are selling shares, it could be an indication that they feel the share price is overvalued and will likely fall.

One of the most common reasons that insiders buy their own stock is to retain control over their companies. By acquiring large amounts of stock, they can potentially exert more influence over board decisions and ensure that they keep a strong hold on power. Another reason for insider buying is to take advantage of short-term price movements; some executives may see an opportunity for quick profits and decide to buy in anticipation of a jump in the share price. And finally, there’s always the possibility that these executives have inside information about upcoming mergers and acquisitions (M&A).

There are some key factors to consider when looking at insider buying. For example, insider buying doesn’t always mean that the company will be profitable in the near future. In addition, it’s important to look at both short term (the last year or so) and long term (the past five years) data when evaluating insider buys.

If you want to find out who's buying up shares of a particular company, you can check the company's SEC filings. Analyzing company filings can be time-consuming, but it's often the best way to track who's buying and selling stock. You can find insider buying and selling transactions by scanning the most recent Form 4 document filed with the SEC.
You can also search for news articles that mention investment companies that are buying lots of stock in a particular company. These kinds of stories are often good indicators that there might be insider buying going on. Of course, insider information isn't always reliable, so it's important to use your own judgment when interpreting these kinds of signals.

The SEC Form 4 is required to be submitted within 10 business days after the transaction.