Micro contracts, and the price of granularity

Exchanges scaled their flagships down for retail, and the scaling is honest: same book logic, same specs discipline, a tenth the multiplier. The trade-off is one ratio, and this lesson computes it.

What granularity buys

• Sizing that fits the arithmetic: module 4's whole-contract problem shrinks by the scaling factor - risk budgets that bought zero full-size contracts buy several micros, and the sizing machinery works as designed.
• Variation flows the account can absorb: a tenth the per-point value is a tenth the nightly demand - lesson 4's budget, scaled to retail cash.
• Honest apprenticeship: the same market, the same machinery, at stakes that let process fail cheaply - the learning case, stated without romance.

What it costs

The stack does not scale with the multiplier: micro round turns run at a substantial fraction of the full-size contract's, so the cost per unit of notional can be up to 10 times the flagship's - the flat-cost regressivity lesson, now as a designed product feature. Spreads add a second ratio: micro books quote wider relative to tick more often, per module 2's family calibration. The honest computation per family: micro round turn plus typical spread cost, divided by micro notional, against the same ratio for the full-size - two lines, and the granularity's price is a number.

The decision, sized honestly

The ratio decides by account size: where full-size contracts fit the risk budget, they are strictly cheaper per unit of exposure; where they do not fit - module 4's arithmetic says so, not preference - the micro's surcharge is the price of sizing correctly, and paying it beats mis-sizing by a wide margin. The wrong outcomes are the two extremes: large accounts paying the micro surcharge from habit, and small accounts forcing full-size contracts to dodge it - the second being module 4's chunkiness problem wearing a cost rationalisation. Granularity is a product; buy it when the sizing arithmetic says so, and not from either kind of pride.