Tick data is the most granular market data format because it records activity as individual events rather than as time-bucketed summaries.

Tick data is the most granular market data format because it records activity as individual events rather than as time-bucketed summaries.

The event stream is defined at the trade and quote level and includes normalized market data built from exchange messages that contain trades and order book updates across venues. In this event-driven structure, each new trade print or quote change is preserved as its own record in sequence. That mechanism makes tick data a direct representation of how market activity arrives, rather than a later aggregation of that activity into bars.

The same distinction explains why tick data has higher resolution than bar data. A bar compresses many underlying events into summary fields over a fixed interval, such as open, high, low, close, and volume. Tick data does not perform that compression. It keeps each trade or quote update as it occurs, so the ordering and timing of microstructure events remain available for analysis.

For quantitative research, this difference matters because the data model is event-driven. Researchers can reconstruct sequences of prints and quote revisions, study cross-venue interactions, and build downstream aggregates from the raw event stream. Starting from bars does not preserve the full path of updates inside the interval, so it cannot provide the same level of detail.

Covered in depth in the Cross-venue market data & signals pillar hub.