Bid-Ask Dynamics and Listing-Day Performance of Indian IPOs: An Empirical Analysis of the Mainboard and SME Segments in 2026

When a private company decides to sell shares to the public for the first time, it enters a high-stakes ritual known as an initial public offering, or IPO. This is the moment a business transforms from a closed group of owners into a public entity, raising money by inviting everyday people and large institutions to buy a piece of it. In India, the price of these shares is not simply set by the company; instead, it is discovered through a process called book building. During a specific window, investors place bids indicating how many shares they want and at what price. The final price is determined by the collective demand, much like a silent auction where the highest bids that can be satisfied set the market rate. Once the shares are sold, they immediately begin trading on the stock exchange, where their value can rise or fall within minutes. This first day of trading is critical. It is often marked by a phenomenon called underpricing, where the shares start trading at a price significantly higher than the price investors paid to buy them. This gap creates an immediate profit for those who managed to secure shares, but it also raises a difficult question: is that profit a sign of a healthy investment, or merely a temporary spike in excitement that will soon fade?

Understanding this distinction is vital because the excitement of the first day often masks the true nature of the investment. For years, researchers have tried to explain why these price jumps happen. Some theories suggest that companies intentionally set the price low to ensure everyone gets shares, while others argue that the market simply does not have enough information to know the true value of a new company, leading to a scramble that pushes prices up. More recently, the focus has shifted to the behavior of the crowd. When investors hear that a new issue is popular, they may rush to buy in, driven by a fear of missing out rather than a careful look at the company's finances. This emotional surge can create a disconnect between the price of the stock and its actual worth. The real test, however, is not just how high the price goes on the first morning, but whether there are enough buyers and sellers to trade the shares smoothly afterward. If a stock jumps in price but no one is willing to sell, or if the gap between what buyers want to pay and what sellers want to receive is too wide, the apparent profit may be impossible to realize.

In a study published in August 2026, Dr. Dasari Rajesh Babu examined exactly this dynamic within the Indian stock market, looking at the performance of new listings throughout that year. The research focused on two distinct categories of companies: the Mainboard, which typically features larger, more established firms, and the SME segment, which is dedicated to small and medium-sized enterprises. The study gathered data on 77 different companies that went public during the fiscal year, tracking how much money they raised, how many of them saw their share prices rise on the first day, and how those gains were distributed. The findings revealed a clear divide between the two groups. The Mainboard companies, though fewer in number, raised a massive amount of capital totaling over 25,000 crore rupees. In contrast, the 56 SME companies listed raised a combined total of roughly 2,600 crore rupees. While the SME segment was much more active in terms of the sheer number of companies listing, the Mainboard dominated in terms of the actual funds mobilized.

The study also looked at the reliability of these first-day gains. Among the Mainboard listings, about 62 percent of the companies saw their share prices finish higher than the price at which they were sold to the public. For the SME segment, the figure was lower, with only half of the listings showing a positive gain. This suggests that while smaller companies are eager to list, they face a higher risk of starting their public life on the wrong foot. The data showed that the average gain across the market was positive, but this average told a misleading story. The actual results were wildly scattered, with some stocks more than doubling in value on their first day, while others lost nearly 40 percent of their value. This wide range indicates that the market was not moving as a single block but was instead reacting to individual stories, with some companies capturing intense excitement and others failing to find any support.

A central argument of the paper is that the traditional way of judging an IPO is flawed. Many investors look at the subscription numbers—how many times the shares were oversubscribed—as a green light to buy. The study argues that this is an incomplete signal. A high number of bids from retail investors, or everyday people, does not guarantee a good investment, especially if institutional investors, who are typically more experienced, are not participating heavily. The research suggests that retail demand can be driven by sentiment and rumors rather than a solid understanding of the company's value. Furthermore, the study emphasizes that the story does not end when the shares start trading. A stock might list at a high price, but if the market for that stock is thin, meaning there are very few people buying and selling, an investor might find themselves unable to sell their shares at that price. This is particularly true for the SME segment, where the trading volume is often low.

To address this, the author proposes a two-step approach for investors. The first step is the decision to bid for the shares during the initial offering. Here, the study advises looking closely at who is buying. Strong interest from large institutional investors is a more reliable sign of value than a frenzy of small retail bids. The second step happens after the stock is listed. Instead of assuming the first-day price is the final word, investors should look at the "bid-ask" conditions. This involves checking how many people are trying to buy versus how many are trying to sell, and how wide the gap is between those two prices. If the gap is wide or if there are many sellers waiting to dump their shares, it is a sign that the price might not hold. The study suggests that for small companies, investors should be especially cautious, as the lack of liquidity can trap them in a position where they cannot exit even if the price looks good on paper.

The research concludes that the Indian IPO market in 2026 was a mix of high activity and uneven outcomes. While the Mainboard provided a more stable environment with larger capital raises and slightly better success rates, the SME segment offered a high volume of listings with much greater volatility. The study does not claim to have solved the mystery of why prices move, but it does provide a clearer map for navigating the chaos. It warns that the excitement of a first-day surge is not a substitute for a careful analysis of who is buying and how easily the stock can be traded later. By separating the decision to buy the shares from the decision to hold or sell them, and by paying attention to the actual depth of the market rather than just the headline price, investors can make more informed choices. The data serves as a reminder that in the world of new stock listings, what looks like a winning ticket on the first day can quickly turn into a difficult position if the underlying support is not there.