> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kuru.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Passive Liquidity Events

> Understand how passive bands affect execution and which events to index.

The matching engine can execute against passive price bands as well as resting limit orders. A band's base and quote inventory changes when trades execute against it.

## How trades use the liquidity

The band exposes buy or sell liquidity at its active edge. Kuru compares that price with resting limit orders and executes the best available price first. At an equal price, passive liquidity executes before resting limit orders.

## Indexing passive activity

Use `TradesPacked` to reconstruct execution-induced changes to active and passive depth. `PassiveBandUpdated` supplies the band's inventory snapshot. Key a band by `(chainId, market, lowPrice)`; do not infer its inventory solely from order-placement events.

See [Order-book indexing](/indexing/order-book) and [SDK events](/sdk/events) for event fields and replay guidance.


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