Kostak Rate vs. Subject to Sauda (Sub2) Explained: A Grey Market Guide

What is the Unofficial Grey Market?

Before an Initial Public Offering (IPO) officially lists on stock exchanges like the BSE or NSE, its shares often trade in an unofficial, over-the-counter market known as the Grey Market. While trading unlisted shares is not regulated by SEBI, tracking Grey Market activity is highly popular among retail investors because it acts as a powerful sentiment indicator.

Within this market, two terms dominate the conversation: Kostak Rate and Subject to Sauda (Sub2). Understanding the difference between these two can help you accurately gauge institutional and high-net-worth investor (HNI) demand.

What is the Kostak Rate?

The Kostak Rate is the fixed premium paid by a buyer for an entire IPO application, regardless of whether the application receives an allotment or not.

For example, if you apply for an IPO and sell your application in the grey market at a Kostak rate of ₹2,000, the buyer pays you ₹2,000 upfront. If your application gets allotted, the buyer takes the shares and the listing gains. If you do not get an allotment, you still keep the ₹2,000, and the buyer takes the loss.

Why trade on Kostak?

For sellers, it completely eliminates risk. For buyers, it is a way to secure a position in highly oversubscribed IPOs where getting a direct allotment is mathematically difficult.

What is Subject to Sauda (Sub2)?

Subject to Sauda (often abbreviated as Sub2) is the premium agreed upon for an IPO application only if the shares are allotted.

For example, if the Subject to Sauda rate is ₹5,000, you agree to sell your application to a buyer. However, the deal is only valid if you actually win the allotment lottery. If you get zero shares, the deal is canceled, and no money exchanges hands.

Why choose Subject to Sauda?

Sub2 rates are generally much higher than Kostak rates because the buyer takes on zero allotment risk. They only pay the premium if the shares are successfully credited to the Demat account.

Kostak vs Subject to Sauda: Which is a Better Indicator?

While both metrics indicate demand, Subject to Sauda is generally considered a more accurate reflection of expected listing gains. When Sub2 rates spike heavily in the days leading up to the IPO allotment, it suggests that large buyers are desperate to acquire confirmed shares at a premium, predicting a massive listing day pop.

However, manually tracking these offline rates can be confusing and risky. Instead of relying on word-of-mouth, smart investors simply monitor the aggregated Grey Market Premium trend. You can instantly check the real-time, aggregated premiums and expected listing gains for any active issue using our Live IPO GMP Tracker.

The Bottom Line

Both Kostak and Subject to Sauda are unregulated grey market transactions. While it is not recommended to participate in these offline trades due to counterparty risks, tracking their rates is an excellent way to predict IPO listing performance. By keeping a close eye on the live GMP trends, you can make highly informed decisions on whether to apply for an upcoming IPO or skip it entirely.