How an iceberg order hides the size of a large trade

Only the tip of an iceberg shows above water. An iceberg order works the same way: the market sees only a small part of a large order. This page explains how iceberg orders work, why traders use them and how they relate to disclosed quantity and freeze limits in India.

Quick answer

An iceberg order is a large order that is split into smaller visible parts, so only a small portion shows in the order book at any time. When one part is filled, the next part is placed automatically. This hides the full size of the order from other traders, which can reduce price impact. In India, exchanges offer a disclosed quantity feature, and many brokers offer iceberg orders that split large F&O orders into smaller slices.

Key takeaways

• An iceberg order shows only a small part of a large order.
• Each slice is replaced by the next once it fills.
• It reduces the signal a large order sends to the market.
• Indian exchanges offer a disclosed quantity feature.
• Brokers' iceberg orders help split F&O orders above freeze limits.

What is an iceberg order?

If a trader places an order for 1,00,000 shares in one go, everyone sees it in the order book. Other traders may move their prices, which makes the order more expensive. An iceberg order avoids this by showing only a small slice, such as 5,000 shares, at a time.

When that slice is filled, the next slice appears, and so on, until the full order is complete or cancelled. To the market, it looks like a series of normal-sized orders.

Why do traders use iceberg orders?

The main reason is to reduce price impact. A large visible order signals strong demand or supply, and others may trade ahead of it. Hiding the full size makes this less likely.

It also helps with exchange limits. In India, futures and options contracts have a freeze quantity, which is the largest order size accepted in a single order. Orders above it are rejected, so large orders must be split.

How does it work in India?

Indian exchanges allow a disclosed quantity in the order entry system. A trader can choose to show only part of the order in the order book, within the minimum disclosure rules set by the exchange.

Many brokers also offer an 'iceberg' order type, mainly for F&O. It splits a large order into several smaller orders, each within the freeze limit, and places them one after another. NSE revises freeze limits from time to time, so traders should check the current limits on the exchange website.

What are the limits?

Iceberg orders do not guarantee a fill or a price. If the market moves away while slices are being placed, later parts may fill at worse prices or not at all. Experienced traders may also spot repeated small fills at the same price and guess a hidden order is present.

Each slice can also carry its own charges, depending on the broker's pricing, so it is worth checking costs.

The key point to remember

An iceberg order shows the market only the tip of a large trade. It is a useful tool for reducing price impact and handling freeze limits, but it does not remove market risk.

Frequently Asked Questions