Insider Dealing: What It Is, How It Works, Why It Persists
Insider dealing is illegal, persistent and hard to spot. Learn how inside information moves, why it matters, and what private investors can check.
Insider dealing is not clever trading. It is using private, price sensitive information before the rest of the market gets it.
The Short Version
- It means trading, cancelling an order, or encouraging a trade while holding inside information.
- Inside information is precise, private and likely to move a share price once published.
- UK rules treat this as market abuse, and serious cases can be criminal.
- Private investors cannot stop it, but they can avoid chasing unexplained price moves.
What insider dealing actually means
Insider dealing starts with information the market does not yet have. The FCA market abuse guide says insider dealing and market manipulation can both amount to market abuse.
In plain English, the problem is unfair access. One person knows a takeover, warning, placing, contract loss or court decision before everyone else.
If that person trades on the information, or passes it to someone who trades, the market is no longer fair. A public market becomes a private advantage.
What counts as inside information
Inside information is not just a rumour. The FCA says it is confidential, non public and valuable enough that disclosure could affect the price of shares or other instruments. Its inside information guidance explains why poor handling can damage market integrity.
The classic case is a takeover. A board, adviser, lawyer or banker may know the deal before the announcement reaches the Regulatory News Service.
Other examples include a profit warning, a major contract, a failed funding round, a regulatory decision, or trial results for a listed healthcare company.
The information must be specific enough to matter. A vague feeling that a company is doing well is not the same as knowing a price sensitive announcement is coming.
How inside information leaks
The leak often begins long before the public announcement. Big corporate events involve bankers, lawyers, accountants, brokers, directors and communications advisers.
Each extra person adds a leak risk. Some leaks are deliberate. Others start as loose talk at lunch, a careless message, or a hint passed to a trusted friend.
The City still runs on relationships. That does not make every relationship corrupt, but it explains why private information can move through informal networks.
This is why suspicious price moves before announcements matter. They do not prove misconduct by themselves, but they can show that information has escaped.
Why insider dealing hurts ordinary investors
This offence is sometimes described as victimless. That is wrong. Every unfair trade has someone on the other side.
If a seller parts with shares at 200p before a 300p bid, they lose a gain they would probably have kept if they knew the truth.
The wider damage is trust. Markets work only when investors believe prices reflect public information, not a hidden queue of people trading first.
That trust affects cost of capital too. Companies raise money more cheaply when investors believe the market is fair and well policed.
How the UK rules work
UK market abuse rules sit beside criminal law. The FCA explains that UK MAR covers civil market abuse. Criminal insider dealing is an offence under Part V of the Criminal Justice Act 1993.
Civil action can lead to fines, bans and other restrictions. Criminal cases can lead to prison and unlimited fines.
The FCA also receives suspicious transaction and order reports from firms and trading venues. These reports help the regulator spot patterns that a private investor would never see.
This does not mean every case is caught. Insider dealing is hard to prove because intent, timing and information flow all matter.
Why insider dealing still persists
Insider dealing persists because the reward can be large and the evidence can be hard to collect. A short message, a coded call or a trade through another account can be difficult to unwind.
Technology has improved surveillance. Regulators can study transaction data, order books and suspicious reports in ways that were impossible decades ago.
But people still create the risk. Deals, funding talks and sensitive announcements pass through human hands before they reach the market.
That is why the offence never disappears completely. The rules can punish it, but they cannot remove temptation from every private conversation.
A Worked Example
Imagine a small listed company is about to receive a takeover bid at 300p a share. The shares trade at 200p before the announcement.
A person involved in the deal tells a friend. The friend buys shares before the bid is public, then sells after the announcement.
That profit did not come from better analysis. It came from information other investors did not have.
Now think about the seller. They may have sold at 200p because the public market gave them no reason to expect a bid.
That is why the offence matters. The unfair gain sits beside an unfair loss.
The checks private investors can use
You cannot investigate market abuse from a home trading account. You can, however, avoid treating every unexplained move as a clean signal.
Start with the RNS feed. Check whether the company has released news, a holding notice, a director dealing notice, or a statement about a possible offer. Our guide to reading a share price listing explains the basic screen first.
Next, look at volume. A sharp price rise on thin volume means something different from heavy, repeated buying through the day.
Then look at the spread and market depth. The post on market makers explains why quoted prices can move quickly when liquidity is thin.
The final check is restraint. If the price has already moved hard before public news, you may be late to information you cannot see.
What This Means For You
Insider dealing should make private investors more careful, not more paranoid. Most unusual price moves are not proof of wrongdoing.
The useful habit is to ask what public information explains the move. If the answer is unclear, size the risk accordingly or wait for a proper announcement.
Our guide to stock market scams covers a different kind of market harm. The post on dark pools and HFT explains why visible prices are only part of the trading picture.
The key point is simple. Do not pay a price that already seems to know tomorrow’s news unless you understand the risk.
In Plain English
It is trading with secret price sensitive information. It is unfair because one side knows something the other side cannot know yet.
The UK has civil and criminal rules against it. The FCA can fine people, ban them, and bring serious cases to court.
For ordinary investors, the lesson is caution. A strange price move may be noise, rumour, or leaked information.
You do not need to solve the case. You need to avoid becoming the person who buys after the hidden information has already moved the price.
This article is for general financial education only. It is not financial advice or personal investment advice. Investments can fall as well as rise, and you may get back less than you invest.
This post is adapted from The Street Smart Trader. Used with permission.