// GLOSSARY

Passive post

Placing an order that rests in the book (at or inside the touch) instead of crossing the spread — trading immediacy for price. You earn the spread and typically pay maker (often zero) fees, at the cost of uncertain and delayed fills.

To post passively is to join the book rather than hit it: a buy placed at or below the best bid (or improving it by a tick) that waits for a seller to come to you.

The economics

Crossing a 42/45 market costs you the 45¢ ask plus, on Kalshi, a taker fee. Posting at 43¢ — improving the bid — costs nothing while it rests, fills 2¢ better if it fills, and generally pays no maker fee on Kalshi. Across hundreds of trades in thin markets, that 2–3¢ per contract is frequently larger than most strategies' edge.

The catch

Passive fills are adversely selected: you're most likely to get filled precisely when the market is moving through your price. The seller who hits your 43¢ bid may know something. Passive posting is therefore a bet that your patience is worth more than their information — usually true for uninformed-flow execution, dangerous for stale quotes. Managing that tension with re-pricing and time limits is the job of a worked order; the routing math is in smart order routing.