IV · Edge mechanisms
Station IV of The Quant Map: why should an edge exist? Name the payer before the indicator. Ten mechanism families. Reading order plus the free map PDF.
why should an edge exist?, the root question of the map
Name the payer before you name the indicator. Reachable money is usually a risk someone better-resourced refuses to warehouse, a capacity limit that makes the trade a rounding error for them, or a flow that has to deal. A $5 million niche earning 40% a year is a living at your size and 0.01% of a $20 billion fund, which is why the fund leaves it. If the answer to "why does this pay" is "the backtest went up," you do not have a mechanism yet.
This is the root question of the map. Ten mechanism families exist: risk premia, behavioral, macro transmission, relative pricing, positioning and leverage, microstructure, volatility, structural and events, information transmission, crypto-native. Every strategy in the library hangs off one of them, and the PDF names the family on each of its 835 rows.
The Quant Map PDF works this spine through example research: five full descents from observation to live rule, and a library of 835 strategy entries, each with a named payer and a named failure mode. Get the free PDF on the Start Here page.
Reading order
Top to bottom. Stop at the first article you cannot apply to a live trade; that is the one to read slowly.
| Article | Why it is on this row |
|---|---|
| The Theory of Edge: Why the Market Pays You | Two checks: why you make money, and why you keep it. The barrier is measured against the participant across from you. |
| Who Is the Marginal Buyer? | Price is the last clip. If you cannot name who bids here, nothing is under the print. |
| Large Trades Are Insider Trades by Definition | Impact scales near the square root of size. The part that does not revert is the information. |
| Predictive Power vs Long Bias: The Hidden Trap in Backtests | A QQQ trend rule's 22% split into about 16% equity drift, 5% tech tilt, and 1% timing. |
| The Carry Trade: Up the Escalator, Down the Elevator | The interest gap is the premium. The crash is the risk you have to date before you hold it. |
| Market Making Is Not Just Collecting the Spread | The job is quoting a fair value and surviving the flow that knows more than you do. |
| Why Fat Tails Are the Reason Trend Following Works | The payer is the holder who cannot sit through the left tail you are being paid to take. |
| Alpha Decay Is Just Competition (and Papers Lie) | Realized edge shrinks as about 1 over (1 plus the number of people trading it). A printed paper is already a crowd. |
On the map: ← III · Market theory · The grand map · V · Observable world →