Quote Staleness

A price feed is a claim: this is where the market is now. Quote staleness measures how far behind “now” that claim runs. Every feed carries some latency — aggregation, transport, and display all take time — so staleness is a spectrum, not a binary. The question is whether a venue’s staleness is an unavoidable few milliseconds of plumbing or a structural property that changes what its clients can know.

Staleness has several distinct causes. Infrastructure latency delays honest quotes. Throttled update cadence — republishing the feed at a coarser interval than the underlying market moves — leaves each displayed quote representing an increasingly historical state between updates. Aggregation across liquidity providers can hold quotes while a composite is recalculated. And at the deliberate end of the spectrum sits tick suppression during fast markets, which is censoring: staleness as policy rather than physics.

The consequences run in two directions. For the trader, decisions keyed to a stale quote are decisions about a market that no longer exists; the resulting fills arrive with systematic slippage, concentrated in exactly the volatile moments when the displayed price lagged most. In the other direction, a persistently slow venue is exploitable by anyone with a faster view of the same market — the raw material of latency arbitrage — and venues aware of this tend to respond with defensive mechanics such as last look, asymmetric rejection, or further throttling, each of which degrades execution for ordinary clients.

Staleness is measurable from the feed itself. Inter-tick arrival distributions, update cadence under calm versus volatile regimes, and timestamp comparison against a multi-venue reference during the same windows together characterise how current a feed actually is. None of that requires the venue’s cooperation — only a recorded feed and its timestamps.