Trading risk for beginners.
Survival is a strategy.

Quick answer

What is trading risk?

Trading risk is the amount and type of uncertainty attached to a position. It includes the risk that price moves against you, that an order fills worse than expected, that a stock gaps through a stop level, that liquidity disappears, or that several positions fall together because they share the same underlying exposure.

A risk plan should exist before the trade, not after the market starts negotiating with your ego.

What is capital at risk?

Capital at risk is the amount you could lose if the trade fails according to your plan. A simple way to think about it is the distance between entry and planned exit multiplied by the position size, then adjusted for fees, slippage and the possibility that the market gaps past the intended exit.

That last part matters. A theoretical stop level is not a guaranteed loss ceiling.

What is position sizing?

Position sizing is deciding how large a position should be relative to your account and the risk of the setup. A position that is harmless at $500 can be catastrophic at $50,000. The chart did not become more certain because you became more enthusiastic.

There is no universal percentage that is correct for every trader. The useful principle is that one losing trade should not be able to threaten the survival of the account.

What is invalidation?

Invalidation is the evidence that would tell you the original interpretation is no longer supported. It can be a price level, structural break, failed catalyst response or other defined condition.

Invalidation and stop placement are related but not identical. One is analytical: when is the idea wrong? The other is executional: how will you act if that happens?

Why does liquidity matter?

Low liquidity can increase spreads, slippage and gap risk. A position may look small in dollar terms but still be large relative to the amount of stock normally available near the current price.

What is concentration risk?

Concentration risk appears when too much capital depends on the same company, sector, commodity, theme or market factor. Owning five mining stocks can look diversified by ticker while still being one concentrated bet on commodity sentiment.

What is gap risk?

Gap risk is the chance that the next available market price is materially different from the previous price. Overnight news, trading halts and company announcements can all create gaps. If price jumps past your planned exit, the actual loss can be larger than the loss calculated from the stop level.

What should a beginner define before entry?

Define the reason for the trade, the evidence that would invalidate it, the intended position size, the approximate capital at risk, known event risks and whether the stock is liquid enough for the planned position. If you cannot answer those questions, the trade is not ready.

Where should you go next?

Continue into Position Sizing Explained, What Is Invalidation?, Stop-Loss Orders, Gaps and Slippage and Drawdown, Liquidity and Concentration Risk.

Educational information only. Shares and trading involve risk of loss; your own financial situation and objectives matter.