Definition

Liquidity

Resting limit orders waiting to be filled. Not static — actively managed by participants in real time.

Full Explanation

Liquidity is what price moves through, not what it bounces off. It is the collection of limit orders sitting at various prices, placed by participants willing to buy or sell at those specific levels but not yet. Deep liquidity at a price means a large amount of opposing aggression is required before price relocates. Thin liquidity means even modest aggression can move price. Liquidity is never fixed — participants add, cancel, and modify their orders continuously, which is why a level that held before may not hold again even though the chart looks the same.

In the Book 1 chapter

Chapter 2 · The Mechanics

Liquidity and Aggression

Every single trade has a buyer and a seller. That’s not an insight — it’s just math. For any transaction to happen, someone has to buy and someone has to sell. Which means that when you hear “buyers are in control right now” or “sellers are pushing price down,” you should pause for a second, because those phrases are telling you less than they sound like they are.

From the Blog 1 post

Why "Buyers vs. Sellers" Is the Wrong Frame

Every transaction has both a buyer and a seller. That's not insight — it's arithmetic. The question that actually matters is different, and until you're asking it, you're working with the wrong map.

Videos 2 videos

Stop Saying "Buyers and Sellers" — Start Saying Liquidity and Aggression

Two people can both be buyers and be doing completely different things in the market . The key is not buyers vs sellers, it is understanding liquidity and aggression.

Why does price actually move?

When aggressive market orders arrive at a price, exactly one of two things happens: the resting liquidity at that price absorbs them and price stays put, or the liquidity is insufficient and price relocates to the next available price.