MARKET MOVEMENT

A better price or a different bet?

Getting −105 at +4.5 when the same book closes −120 at +4.5 improves the price at the same threshold. The raw break-even rate moves from 51.22% to 54.55%, about 3.33 percentage points.

Keep the payoff fixed

If the spread changes from +4.5 to +3.5, a four-point loss covers the first number and loses on the second. Record threshold movement separately unless you have a defensible way to price that change.

What to record

Keep the sportsbook, quote timestamp, capture timestamp, line, opposite price and settlement rules. Report the number of matching closes. Closing-line value is a market comparison. Realized return requires settled results and costs.