What is IOC in Stock Market?
Introduction
Have you ever tried ordering something online, but it went out of stock before you could click “buy”? That’s sort of what happens in stock trading with certain types of orders. One such order is IOC, or Immediate or Cancel. It's a term often used in the world of stock markets and online trading platforms. But what exactly does it mean? And more importantly, how does it impact your trading decisions?
In this guide, we’ll break it down for you in the simplest way possible. No confusing jargon. Just clear, conversational explanations. You’ll also get to know how IOC orders fit into today’s tech-driven world, including insights into the best algo trading software in India, the best algorithmic trading software India, and how online trading software handles IOC orders.
Learn what IOC means in stock trading & how it works. Explore best algo trading software in India, best algorithmic trading software India & online trading software.
What Does IOC Stand For?
IOC means Immediate or Cancel. It’s a type of order that tells the trading system: “Execute this order right away. If it can’t be filled immediately, cancel the remaining part.”
Think of it like asking a waiter, “Bring me whatever pizza you have ready now. If you don’t have it, forget the order.”
This type of order is commonly used in fast-paced environments like intraday or algorithmic trading where time is critical.
How Does an IOC Order Work?
Let’s say you place an IOC order to buy 500 shares of a stock at ₹100. If only 200 shares are available at that price, the system will buy those 200 instantly and cancel the remaining 300.
No waiting. No delays. No pending orders.
This ensures you don’t get stuck with partial orders sitting in your portfolio or unexpected price changes.
IOC vs Other Order Types (FOK, GTC, Day Orders)
To really understand IOC, it helps to compare it with other common order types:
Order Type
Behavior
IOC
Fills immediately, cancels the rest
FOK (Fill or Kill)
Must fill entire order instantly or cancel completely
GTC (Good Till Canceled)
Stays active until manually canceled
Day Order
Active only for the trading day

IOC is the middle ground—it allows partial fills unlike FOK, but won’t wait around like GTC or Day Orders.
When Should You Use an IOC Order?
You might use an IOC order if:
You want immediate execution.

You’re trading large volumes and don’t want leftovers.

You’re running an automated strategy using algo or online trading software.

Market conditions are volatile, and prices change fast.

In simple terms, if time is money in your trading strategy, IOC is your best friend.
Benefits of Using IOC Orders
Here are some clear benefits of using IOC orders:
Speed: Instant execution or cancellation.

Efficiency: No leftover pending orders.

Control: Helps avoid price slippage.

Automation Friendly: Perfect for algorithmic and high-frequency traders.

Risks and Limitations of IOC Orders
Of course, nothing is perfect.
Partial Fills: You might only get part of your order.

Missed Opportunities: If the stock becomes available seconds later, you miss out.

Complexity: Not ideal for beginners unless supported by smart software.

IOC Orders in Intraday and Delivery Trading
Intraday Traders often prefer IOC to capitalize on quick price movements.

Delivery Traders may use it to avoid holding unfulfilled parts of an order overnight.

In both cases, IOC adds a layer of control and speed to your trades.
How to Place an IOC Order on Online Trading Software
Most online trading software platforms like Zerodha, Upstox, or Angel One allow placing IOC orders in just a few clicks.
Steps:
Open the stock/order screen.

Select ‘IOC’ under order type.

Enter your quantity and price.

Confirm and place the order.

Some platforms even auto-recommend IOC for fast-moving stocks.
IOC in the World of Algorithmic Trading
Algo traders rely heavily on IOC because:
They need instant execution.

Their strategies run on logic: if not filled now, move to the next opportunity.

They deal in high volumes that may not always fill completely.

IOC helps reduce execution risk and slippage, two big enemies of algorithmic trading.
Best Algo Trading Software in India for IOC
Let’s look at the best algo trading software in India that handles IOC orders smoothly:
Quanttrix – Offers real-time IOC placement in milliseconds.

Tradetron – Drag-and-drop strategies that support IOC logic.

Streak by Zerodha – Beginner-friendly interface with IOC capability.

AlgoTest – Ideal for backtesting IOC-based strategies.

All these platforms allow automated IOC execution with ease, making trading faster and smarter.
Best Algorithmic Trading Software India: Top Picks
Here are the best algorithmic trading software India offers:
Software
Key Features
Quanttrix
Fast execution, IOC support, smart interface
AlgoTrader
Global-grade algorithmic trading software
Streak
Perfect for retail traders new to algo
Amibroker + Plugin
Powerful backtesting, IOC with brokers

Each platform helps you automate your trading with precision, and IOC is often a core function.
IOC and High-Frequency Trading (HFT)
High-Frequency Trading (HFT) thrives on speed and execution. IOC is a natural fit here.
Algorithms place hundreds of IOC orders in milliseconds.

If not filled instantly, the algo moves on—no emotional hangups.

It’s like a race car that doesn’t stop for red lights—it just reroutes.

This is where the real power of IOC shines.
Case Study: Using IOC in Real-Time Markets
Scenario:
A trader uses Quanttrix to place 5 IOC buy orders on a volatile stock during market open. Out of 5, 3 get partially filled within 0.8 seconds.
Result:
Partial execution = Quick profits as price jumped immediately.

Unfilled parts = Cancelled automatically, avoiding higher cost later.

Overall = Strategy succeeded due to IOC precision.

Common Mistakes to Avoid with IOC Orders
Not checking liquidity: IOC in a thin market = No fill at all.

Wrong price setting: Too aggressive = No match, too loose = Slippage.

Overuse: Not every situation needs IOC. Know your strategy.

Always test your strategy using demo accounts or paper trading before relying heavily on IOC.
Conclusion & Key Takeaways
IOC orders might sound like a technical term reserved for Wall Street experts, but they’re surprisingly practical—even for retail traders.
Here’s what you should remember:
IOC = Immediate or Cancel.

Great for speed, control, and automation.

Perfect fit for algo and online trading software.

Best suited for fast-moving strategies where timing is everything.

In a world that’s more digital than ever, knowing how to use IOC smartly can give you a serious edge in the stock market.

FAQs
What is the difference between IOC and FOK orders?
IOC allows partial fill and cancels the rest, while FOK must be filled completely at once or not at all.
Can beginners use IOC orders effectively?
Yes, but they should practice first using demo accounts or paper trading platforms.
Which is the best algo trading software in India for IOC orders?
Quanttrix,Streak are among the best for handling IOC efficiently.
Are IOC orders good for long-term investing?
Not really. IOC is better for intraday or high-frequency trading, not buy-and-hold strategies.
Is IOC available on all online trading software?
Most modern platforms support IOC, but always check with your broker or software provider first.