Delta vs Gamma The Hidden Feedback Loop Forcing Relentless Buying on $1 Moves

A stock moves $1. Nothing dramatic, happens 100 times a day. But behind the scenes, that $1 move just forced somebody to go out and buy shares. Not because they wanted to, because they had to. Move it another dollar, and they have to buy more. And here's the strange part: the second dollar makes them buy more than the first one did. That acceleration is the engine underneath everything in options market structure. It has 2 names: Delta and Gamma. Let's make them simple. Quick recap in case you're jumping in here: when you buy an option, a dealer usually takes the other side. They don't want a directional bet, so they immediately hedge it by trading real shares in the real market. That hedge is actual buying or selling pressure. The question this video answers is, how many shares? Because the answer isn't fixed. And that's where it gets interesting. Delta is one number that answers one question: How much does this option behave like the actual stock? That's it. Forget the Greek letter. Delta is: How many shares does this option act like right now? Say our stock is at $100, and we're looking at call options. A call way up at $130 is a long shot. If the stock moves a dollar, that option barely reacts. It acts like maybe 5 shares. Low Delta. A call right at $100 is a coin flip. If the stock moves a dollar, the option moves about 50 cents. It acts like 50 shares. That's the classic mid-range Delta. And a call way down at $70 is almost certain to finish in the money. It moves nearly dollar for dollar with the stock. It acts like 100 shares— basically, the stock itself. High Delta. So delta slides from near 0 to near 100 shares, depending on where price sits relative to the strike. That's the whole concept. Now delta becomes an instruction. A dealer sold you 1 call. That call currently acts like 50 shares. So to cancel the risk, the dealer buys 50 shares. Not 100. 50. Exactly enough to offset what the option is currently doing. Delta isn't theory to them. It's the order size. It tells them precisely how many shares to buy or sell to stay neutral. Here's the catch, and it's the whole reason gamma exists. Delta is not a fixed property. It changes constantly because it depends on where price is right now. That call at $100 acts like 50 shares today. If the stock rallies to $103, that same contract now looks a lot more likely to pay off, so So it starts acting like 65 shares. Rally further, and it acts like 80. Same contract. Same strike. Completely different amount of stock-like behavior. And that's gamma. Gamma is simply how fast delta changes when price moves. If delta is the speed, gamma is the accelerator. High gamma means delta shifts quickly with every tick. Low gamma means delta barely budges. That's it. 2 numbers, and the second one just describes how fast the first one moves. Now, put the 2 together, and you get the mechanism. Our dealer hedged with 50 shares. Then, the stock rises a dollar. The option now acts like 60 shares. So the dealer is underhedged. They have to go buy 10 more. Stock rises again. Now it acts like 75. Buy 15 more. They can't hedge once and walk away. They have to keep re-hedging, continuously, all day long, as price moves. And notice the direction— price went up, and the hedging response was to buy. Buying pushes price up, which changes delta again, which forces more buying. That's a feedback loop, and it's why moves sometimes seem to feed on themselves for no visible reason. Gamma isn't spread evenly. 2 things concentrate it. The first is distance. Gamma is highest for strikes close to the current price and drops off fast the further away you get. A far out-of-the-money option barely reacts to anything, so there's almost nothing to re-hedge. The second is time. The closer an option gets to expiring, the more violent gamma becomes. With a month left, a $1 move barely changes the odds. With hours left, that same dollar can flip a contract from worthless to in-the-money, so delta swings from near nothing to near 100 shares almost instantly. Near-the-money, near expiry— that's where hedging gets most intense. So, bring it back to the chart. Remember from the open interest video— contracts pile up at specific strikes. Now add gamma to that picture. When price is far from a heavily loaded strike, that strike's gamma is low. It's quiet. Almost nothing is happening. But as price walks toward it, gamma climbs, and every tick forces more re-hedging. The activity that was background noise a few dollars ago becomes the dominant flow in the stock. That's the real reason a big strike behaves like a level rather than just a number on a chain. It isn't the open interest alone; it's open interest plus gamma waking up as price arrives. One honest caveat before we close: because this is where a lot of content oversimplifies. Everything I described assumed the dealer is on the short side of those options, which is the common case when the public is buying. In that setup, hedging chases price— buying into rallies, selling into declines. That's the loop that amplifies moves. But dealers aren't always on that side. When they're positioned the other way, the same mechanics run in reverse. Hedging leans against price instead of chasing it, Selling into strength and buying into weakness. Calm, pinned, range-bound. Same gamma, opposite effect on the tape. Which side dominates is the single biggest reason a stock can feel dead one week and violent the next, and that's its own video. So, to recap, delta is how many shares an option acts like. Gamma is how fast that number changes when price moves. Together, they tell you the size of the hedge and how often it has to be adjusted. And that's why a $1 move can force buying, and why the next dollar forces more. MobyTick maps where that positioning is concentrated and plots those levels on your chart, so you can see which strikes are close enough to matter before price gets there. Next in the series: What happens when dealers are positioned the other way? The difference between a market that pins and a market that whips.