> For the complete documentation index, see [llms.txt](https://fx100.gitbook.io/fx100-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://fx100.gitbook.io/fx100-docs/how-the-system-works/available-liquidity.md).

# Available liquidity

What bounds the size you can open.

There is no order book, so the depth available to you is not set by other traders' resting orders. It is set by the vault and by per-market risk limits.

```
availableLiquidity = min(
    maxOpenInterest − currentOI,            // hard OI cap for the market and side
    poolValue · reserveFactor − reserved     // what the pool will back for this market
)
```

...and any other configured risk limits. The tightest binding constraint wins.

## Open interest caps

Each market has a hard cap on total open interest, applied per side. Once the cap is reached, no further positions can be opened on that side until existing ones close.

This bounds how much exposure the vault can take to any single asset, which matters because the vault backs every market simultaneously.

## Reserve factor

Each market is configured with a ratio governing how much of the pool's value can back positions in that market. Deeper, more liquid assets carry a higher reserve factor; smaller or more volatile assets are set more conservatively.

The larger the pool and the higher the reserve factor, the more depth is available.

## What happens when liquidity is insufficient

Your order is rejected or cancelled. It is not queued and not partially filled.

If you are trying to open a large position in a smaller market, check the available liquidity figure before placing the order rather than after. When the binding constraint is the open interest cap, splitting the order across several fills does not help — the cap is a hard limit on total exposure, not a per-order one. When the constraint is [depth spread](/fx100-docs/trading/pricing-and-execution.md), the order can still fill; it simply prices in the impact a large size puts on the vault.

## Diversification

Because one vault backs every market, LP exposure is diversified across assets rather than concentrated in a single pair. Market-specific caps prevent any one market from consuming a disproportionate share of that capital.

See [the USDC vault](/fx100-docs/providing-liquidity/the-usdc-vault.md).