How the GE matches offers

Every offer you place joins a queue you are never shown. The rules that queue follows explain almost every confusing thing the Grand Exchange does: why an offer filled at a better price than you typed, why yours sat while someone else's went through, and why the number on the offer screen is not a price anyone is trading at.

The OSRS Wiki is honest about this: the exact internals of the Grand Exchange have never been published, and what players know comes from a mix of an old Jagex forum post and years of watching offers behave. What is documented, though, is enough to trade on, and most flippers never learn it. This lesson sticks to the documented rules and says plainly where the ground is softer.

The order book you cannot see

Picture two stacks. On one side sit every unfilled buy offer in the game for a given item, sorted by price, the highest bid at the top. On the other side sit every unfilled sell offer, sorted the other way, the lowest ask at the top. That pair of stacks is the market for that item. Real exchanges show it to you. The Grand Exchange does not show you any of it: you get a single guide price and a text box.

Everything else in this track follows from that one fact. You are trading blind against a structure that exists and behaves in predictable ways, so most of the skill in flipping is inferring the shape of those stacks from the only things you can observe, which are how fast your offers fill and at what price.

The matching rule

A trade happens when one player's buy offer is greater than or equal to another player's sell offer. That is the whole condition. There is no negotiation, no partial agreement, no waiting period. If you place a buy at 800,000 and someone somewhere has a resting sell offer at 795,000, the two match immediately.

Note what this does not say. It does not say your offer needs to equal the guide price, or beat some hidden threshold, or wait for a tick cycle. If the two numbers overlap, the trade is done. If they do not overlap, nothing happens no matter how long you wait, and your offer simply sits in the stack until something changes.

What price the trade actually happens at

This is the part that surprises people, and it is documented. When two offers match, the price is set by whichever side was there first.

• You place a buy and lower sell offers already exist. The trade happens at the lowest existing sell offer, and you get the difference back as gold.
• You place a sell and higher buy offers already exist. The trade happens at the highest existing buy offer, and you receive more gold than you asked for.

In both cases the side that was waiting sets the price and the side that arrived gets the better end of it. That is why the Grand Exchange rewards being the one who crosses the gap rather than the one who sits in it, at least on the price you pay. It is also why your collection box sometimes has coins in it after a buy you thought was exact.

Why overpaying is safe, and why it is not free

The refund makes an aggressive buy offer look risk free. It mostly is, for the instant in which it executes. The trap is what happens to the part of your offer that does not execute instantly.

Suppose you place that 820,000 buy for 70 whips and only twelve are sitting on the sell side under your price. Twelve fill at the sellers' prices and refund you the difference. The other 58 stay in the stack as a live buy offer at 820,000. From that moment on you are the side that was there first, which flips the rule around: any seller who arrives afterwards and places a sell offer below 820,000 trades against your resting bid at your price, not theirs. They get more gold than they asked for, funded by you.

Time priority: the queue behind the price

Price is the first sort. Time is the second. Where several offers sit at the same price, older offers are loosely prioritised over newer ones. The wiki uses that word "loosely" on purpose, because nobody outside Jagex has verified how strict it is, but the direction is clear and it matches what players see.

For you this means matching an existing price is the worst of both worlds on a busy item. If eleven people are already buying nature runes at 135 and you join at 135, you are twelfth in line for every rune that gets sold into that price. You will fill eventually, and eventually can be a very long time on an item where the price moves every few minutes. One gp higher puts you at the front of a queue of one.

That single gp is the whole subject of lesson 3, and the answer is not always to pay it. On a thin item there is no queue to jump, and the gp is wasted. On a heavily traded item there is a real queue, and the gp is the cheapest thing you will buy all session.

Partial fills

An offer for 5,000 items is not one trade. It is up to 5,000 trades against whoever happens to be on the other side, and it fills in pieces as they arrive. The interface shows this with its own colour for a partially completed transaction, and coins and items from partially finished trades can be collected from any bank at any time without cancelling the rest.

Two practical consequences. First, you can and should collect from a running offer, especially on a long sell, so the gold is back in your bank working rather than locked in a slot. Second, the average price of a partially filled buy is not the price you typed. Each piece filled at whatever the seller's ask was at that moment, so a large aggressive buy against a thin sell stack can end up with a genuinely worse average than the first fill suggested. Check the total spent, not the offer price, before you compute your margin.

What instant buy and instant sell really mean

Flippers talk about the insta-buy price and the insta-sell price as if they were two published numbers. They are not published anywhere. They are shorthand for two questions: what is the lowest sell offer currently resting, and what is the highest buy offer currently resting? Buy at or above the first and you fill immediately. Sell at or below the second and you fill immediately. The distance between them is the spread, and it is the only thing a flipper actually gets paid for.

Because those two numbers are invisible, you have to estimate them. The two honest ways are to look at what has recently traded, which is what the Margins board and every item page on this site are built from, or to test the market directly with a one item probe, which is the next lesson.

The guide price is a rear-view mirror

When you open an offer, the Grand Exchange pre-fills a price. That is the guide price, and the wiki describes it as an automatically updated figure based on the item's trade history, intended to represent its approximate market value.

Read that carefully. It is built from trades that already happened. It is not the current lowest ask, it is not the current highest bid, and it is not a price anybody is obliged to accept. On a heavily traded item it stays close enough to be a reasonable anchor. On a rarely traded item it can be badly stale: the wiki notes that low volume items such as partyhats update every few days or even once a week, and can be inaccurate. Jagex also reserves the right to set prices manually where they believe manipulation has gone too far, or where an inflated guide price is being used to scam people.

So treat the pre-filled number as a starting position for your typing, never as evidence. If your entire plan is that an item is trading below its guide price, you do not have a plan, you have a stale number.

Slots, and offers that outlive your attention

Members get eight Grand Exchange slots, free players get three, and each slot holds one buy or one sell. Eight is the real constraint on a flipping session, not your bank, which is why width across several items usually beats depth in one.

Offers do not expire on a timer. A sell offer placed by a member keeps running even if that membership lapses before it fills, and there is no restriction on selling regardless of membership status. The one documented interruption is inactivity: if a player has been logged out for several days, unfulfilled offers pause until they log back in. Buying is separately restricted by the four hour buy limit, which is per item and is covered in GE tax and buy limits.

Eight is a budget, and a budget you cannot see is one you overspend. Track each flip as you place it and My Flips lists what is currently committed, which is the only reliable answer to how many slots you actually have free.

Using this at the offer screen

• Type the price you are willing to trade at, not the price you hope for. A buy above the lowest ask fills at the ask and refunds you. A buy below it just joins the queue.
• Assume a queue exists on liquid items. Matching the current price on an item trading tens of millions of units a day means waiting behind everyone who got there first.
• Cancel the tail of an aggressive buy. Once the easy fills are done, the rest of that offer is a standing invitation for sellers to hit your number.
• Collect from running offers. Partial fills are collectable, and locked gold earns nothing.
• Never price off the guide value alone. It describes the past, and on thin items it describes a fairly distant past.

The next lesson turns the invisible order book into something you can measure. A one item buy and a one item sell, thirty seconds apart, will tell you more about the current state of a market than any chart will.

Item pages used above

Live buy and sell prices, daily volume and buy limits for the items in this lesson: Abyssal whip, Nature rune and Magic logs.

GE Uncut is an unofficial, fan-made tool, not affiliated with or endorsed by Jagex Limited. RuneScape and Old School RuneScape are trademarks of Jagex Limited; in-game content and item images are the property of Jagex Limited, used for reference only. Price data is from the OSRS Wiki real-time prices API. See data attribution.