How old is the price on your screen
Why does the line move between clicking and confirming?
Every price you are looking at is a claim about the past. The question is how far past, and no screen tells you.
There is a floor under the answer that has nothing to do with your connection: the feed itself takes time to see a change and hand it on. This engine will not price a quote as fresher than 2 seconds when the provider did not stamp it — a stated prior, not a measurement of any feed, and it is never zero, because zero is the one value that is certainly wrong.
How fast a quote dies
Modelling survival as exponential with a mean lifetime of 60 seconds on a main moneyline — again a stated prior until your own accept and reject record replaces it — the chance a quote is still there when your bet lands:
| Quote age | Still there |
|---|---|
| 2s | 96.7% |
| 5s | 92.0% |
| 10s | 84.6% |
| 30s | 60.7% |
| 60s | 36.8% |
Half of them are gone by 41.6 seconds.
Why this changes the number, not just the mood
An edge you cannot take is not an edge. A 3% overlay on a quote already 30 seconds old is worth 1.82% once it is multiplied by the chance the price survives to your bet. Those two numbers should never be shown without each other. Most screens show the first and let you discover the second by losing to it.
It also explains the rejections. A bet declined at the moment of placement is usually not a limit — it is a price that had already moved before you clicked, on a market where the survival curve is steep.