How Order Matching Works

TSMx is a peer-to-peer exchange — there’s no house on the other side. When you back a selection, the engine pairs you with another user backing the opposing selection. Your order is “matched” when that counterparty is found.

Why two equal amounts don’t always fill the same way

Because each side of a market is at different odds, equal dollar amounts don’t match one-for-one. The favorite is cheap to fill; the underdog is expensive to fill. The rule: $1 at decimal odds d matches against $(d − 1) on the opposing side.

A worked example

The Knicks are -227 favorites (decimal 1.44) and the Spurs are +227 underdogs (decimal 3.27).

• A $200 order on the Knicks (-227) needs only $0.44 of opposing money per $1, so it fills quickly — often showing $200 matched of $200.

• A $200 order on the Spurs (+227) needs $2.27 of opposing money per $1. It can absorb up to $454 before it’s full — so until enough arrives, it might show, for example, $137 matched of $200.

Partial fills are normal

Two $200 orders side by side — one fully matched, one partially — is not an error. At -227 vs +227 they were never going to fill dollar-for-dollar. The unmatched part keeps filling as more opposing orders arrive, or rests until the market closes. Every cent is accounted for.

Tip

Switch to Decimal odds in your settings to see matching more clearly. American odds make two orders look like they should fill evenly when they won’t.