Guide to Imbalance Only (IO) Orders

By Intrinio
December 13, 2023


In the fast-paced world of financial markets, traders and investors are always on the lookout for tools and strategies to gain an edge. One such tool that has gained popularity in recent years is the Imbalance Only (IO) order. In this comprehensive guide, we will dive into what IO orders are, important considerations when using them, provide an illustrative example, and show you where to access valuable IO order data through Intrinio's robust platform.

What is an Imbalance Only (IO) Order?

Understanding IO Orders

Imbalance Only (IO) orders are a specific type of order used in the context of market auctions, particularly during the opening and closing auctions. These orders are designed to take advantage of imbalances between buy and sell orders that occur during these auction phases.

The Auction Process

Before delving into IO orders, let's briefly understand how market auctions work. Opening and closing auctions are critical periods during the trading day when the market determines the opening and closing prices of securities. During these auctions, traders submit a multitude of buy and sell orders, leading to an auction imbalance when there is a significant disparity between the two sides.

IO Orders Defined

IO orders are limit orders that will only execute if there is an imbalance in the auction. In other words, these orders will sit dormant until the market reaches a state of imbalance, at which point they will be triggered and executed at the prevailing market price.

IO Order Considerations

Advantages of IO Orders

  • Price Improvement: IO orders allow traders to potentially execute at a better price than what is initially available in the order book. This can lead to cost savings and improved trading results.
  • Reduced Market Impact: By waiting for an imbalance to occur, IO orders can minimize the market impact of a large trade, reducing the likelihood of moving the market against the trader's position.
  • Increased Liquidity: These orders can contribute to liquidity in the market by providing a source of potential execution during auctions, encouraging more participation.

Important Points to Consider

  • Auction Strategy: Implementing IO orders effectively requires a clear auction strategy. Traders need to analyze market conditions, historical auction data, and the behavior of market participants to determine when and how to use IO orders.
  • Risk Management: As with any trading strategy, risk management is paramount. Traders should set appropriate price limits and quantity limits for their IO orders to control potential losses.
  • Market Data: Access to real-time market data is crucial when using IO orders. Traders need to monitor the market closely to identify the onset of an imbalance and trigger their IO orders accordingly. Consider of taking a free trial of one of Intrinio’s market data feeds, like Nasdaq Basic, IEX Real-Time Stock Prices, or 15-Minute Delayed SIP.

Example of an IO Order

To illustrate how an IO order works, consider the following scenario:

Scenario: You are a trader looking to buy shares of Company X during the opening auction. The stock is currently trading at $50 per share, but you believe there may be a temporary drop in price during the auction due to a large sell imbalance.

Your Strategy: You decide to place an IO buy order with a limit price of $48. This means your order will only execute if the market reaches an imbalance that drives the price down to $48 or below.

Market Activity: As the opening auction begins, there is indeed a sell-side imbalance, and the stock's price drops to $47 due to increased selling pressure.

Execution: Your IO buy order is triggered, and you purchase shares of Company X at $47 per share, securing a more favorable price than the initial market price of $50.

Where to Find Data for IO Orders (Intrinio)

Accessing reliable data is essential for effectively using IO orders in your trading strategy. You’ll probably need access to a traditional market data feed and other data sets. Intrinio provides a wealth of market data to empower traders and investors. Here's how you can find this data on the Intrinio platform:

  • Create an Account: Start by creating an account on the Intrinio platform. Choose a subscription plan that suits your data needs.
  • Navigate to Market Data: Once logged in, navigate to the market data section, where you can explore various types of market data.
  • Customize Your Data: Use Intrinio's powerful customization tools to tailor the market data to your specific requirements. You can filter by asset class, exchange, date range, and more.
  • Real-Time Updates: Intrinio provides real-time updates, ensuring you have access to the latest data as it becomes available.
  • Technical Support: If you have questions or need assistance, Intrinio offers technical support to help you make the most of our platform and data.


Imbalance Only (IO) orders are a valuable tool in the arsenal of traders and investors, offering the potential for price improvement and reduced market impact during auction phases. By understanding the intricacies of IO orders, considering key factors, and accessing reliable data sources like Intrinio, you can enhance your trading strategy and make more informed decisions in today's dynamic financial markets. Remember that successful trading involves careful planning, risk management, and continuous learning. Happy trading!

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