Dealers & Why They Hedge

Every option you buy has someone on the other side. Most of the time that someone is not another trader with an opinion — it's a dealer whose job is simply to be there, ready to trade, all day long. Understanding who they are and how they manage their risk is the hinge of this whole track: once you see why they must trade when the market moves, the patterns in the terminal start to make sense.

Who is the dealer?

A dealer — also called a market maker — is a firm that quotes prices on both sides of the market at the same time. They post a price they'll buy at and a slightly higher price they'll sell at, and they hold those quotes up continuously.

Think of a currency booth at the airport. It will buy your dollars and sell you euros at any moment, no appointment needed. It doesn't care whether the dollar is about to rise or fall — it makes its living on the small gap between its buy price and its sell price. A dealer in options works the same way, just with contracts instead of cash.

That small gap is the spread. It is where the dealer's profit comes from — not from guessing direction.

Why dealers end up holding inventory

Here's the problem. The dealer can't choose who trades with them. If lots of customers want to buy calls today, the dealer ends up having sold a pile of calls — because for every buyer there must be a seller, and the dealer is the one standing there saying "yes" to all of it.

So the dealer accumulates inventory: a book of option positions they didn't pick for their own opinion, but accepted in order to keep quoting. They might be short thousands of calls or long thousands of puts simply because that's what customers happened to demand.

And as we saw in Options 101, the seller of an option carries an open-ended obligation. A dealer who has sold a lot of calls is now exposed to the market moving against that position — exactly the directional risk they don't want.

The fix: hedging

To strip out the direction they never wanted, the dealer hedges.

To hedge means to take a second position that cancels out the risk of the first. If the dealer's option book would lose money when the market rises, they buy some of the underlying — so a rise lifts the hedge by the same amount the options fall. The two move in opposite directions and roughly cancel.

A simple picture: imagine you sold a friend the right to buy your bicycle next month for $100. If bicycles suddenly get popular and the price jumps to $150, you're on the hook to hand yours over for $100 — a $50 loss. But if you had quietly bought a spare bike for $100 today, you now own something worth $150 to offset that obligation. You no longer care which way the price goes. That's hedging: you've neutralised the direction and kept only your fee.

The specific amount of underlying a dealer must hold to stay neutral is set by the option's delta — the sensitivity you met in The Greeks. Match the delta with the right amount of the underlying and the position is, for the moment, direction-free.

Why the hedging is mechanical and predictable

This is the part that matters most for everything you'll see in the terminal.

Delta is not fixed — it shifts as the market moves (that change is gamma). So a hedge that was perfect a minute ago is slightly off now, and the dealer has to top it up. As the market moves, they trade the underlying again. And again. Not because they have a view — but because their risk rule requires it.

1. 1Price moves up

   Spot rallies into the dealer book.

   ↓→
2. 2Dealer delta shifts

   Short gamma → dealers grow shorter as price rises.

   ↓→
3. 3Dealer must hedge

   To stay neutral they BUY into the rally.

   ↓→
4. 4Flow hits price

   Buying adds fuel — the move accelerates.

↺

Amplifying loop: Each turn pushes price further from where it started. The flow in step 4 feeds back into step 1.

The market moves

Spot rallies into the dealer's book. Nothing has been decided yet — this is just price doing what price does.

Delta shifts

The move changes the dealer's delta— because delta itself moves with the market (that's gamma). The hedge that was perfect a minute ago is now off.

Forced to hedge

To get back to neutral they must trade the underlying again — not because they have a view, but because their risk rule requires it.

Flow feeds price

That hedge is itself a flow into the market. The next move arrives, and the cycle repeats. The dealer is reacting, not deciding — over and over.

Follow the loop above. The market moves, which changes the dealer's delta, which forces them to buy or sell the underlying to get back to neutral, which is itself a flow into the market. Then the next move arrives and the cycle repeats. The dealer is reacting, not deciding.

Two regimes, opposite footprints

The direction of that forced hedging depends on what the dealer is holding, and it isn't always the same.

• When dealers are long options (long gamma), their re-hedging leans against the move — they sell as the market rises and buy as it falls. This tends to dampen swings.
• When dealers are short options (short gamma), the loop flips — they buy as the market rises and sell as it falls, amplifying the move instead.

You don't need the full mechanics yet — that's the next two lessons. For now just hold the shape: same predictable loop, but the sign can either calm the market down or speed it up.

What to carry forward

• A dealer quotes both sides and earns the spread on volume — they don't want a direction.
• Filling customer orders leaves them holding inventory they didn't choose.
• They hedge with the underlying to cancel the unwanted direction, sized by delta.
• Because delta keeps shifting, hedging is a repeating, rule-driven loop — mechanical and largely predictable.
• Whether that loop dampens or amplifies moves depends on the regime.

Next we measure that pressure directly: gamma exposure, the number that says how hard dealers will have to hedge — and where it flips from calming to amplifying.

Next step

Read the hedging flow.

Notable flow surfaces the prints dealers are reacting to, with the resulting hedge direction.

See live flow →