Market Reaction to Insider Trading: Evidence from Regulatory Orders in India

by Arjun Gupta, Sonam Patel, and Renuka Sane.

Introduction

Market integrity depends on effective enforcement against market abuse. When regulators credibly sanction violations, they reinforce investor confidence and reduce the risk premiums that markets impose for uncertain governance. In developed markets, evidence suggests that enforcement achieves this objective: SEC enforcement actions in the United States produce abnormal stock price declines of $-0.5\%$ (Persons, 1997), and UK sanctions trigger reputational losses that far exceed the direct penalties (Armour et al., 2017). This appears to be true, especially for insider trading enforcement. (Persons, 1997) documents significant negative abnormal returns following the SEC's announcements of insider trading enforcement actions. (Engelen, 2012) finds that a clear negative abnormal return on the day of even newspaper coverage of the illegal insider trading practice of CEOs.

An open question, however, is whether this pattern extends to India. We investigate this by examining stock price movements around two types of insider trading enforcement actions in India: final SEBI adjudicatory orders and appellate decisions by the Securities Appellate Tribunal (SAT). We focus on insider trading orders as they can be a signal about the quality of the firm's internal governance. If insiders are trading on privileged information, it suggests that boards, compliance functions, and internal controls are weak, leading to investors discounting the stock accordingly. Further, when the firm and its executives face potential penalties, disgorgement, or other sanctions, these can impose direct costs on the firm and may affect its ability to attract capital and talent. The insider trading laws in India are quite expansive, and cover not only connected persons, but also those who just have access to unpublished price sensitive information, or if there have been some minor disclosure violations. All orders, therefore, may not signal governance issues within a firm. We therefore also look at orders by violation severity and type of insider relationship.

Empirical Strategy

We use an event-study methodology to test whether Indian stock markets react to SEBI enforcement actions and outcomes challenged before SAT. We compile a list of individuals and entities against whom an insider-trading order was issued, then identify the companies whose scrip was alleged to have been insider traded, map them to their corresponding order dates (event dates), and use these firm-event pairs to check for market reaction.

Estimation Procedure

We estimate each firm's normal return using the market model over an estimation window of 210 trading days ending 11 days before the event ($t = -210$ to $t = -11$):

\( R_{it} = \alpha_i + \beta_i R_{mt} + \varepsilon_{it} \)

where $R_{it}$ is the daily return of stock $i$ on day $t$ and $R_{mt}$ is the daily return on the Nifty~50 Index. The Abnormal Return (AR) on event day $t$ is the difference between the actual return and the predicted normal return:

\( AR_{it} = R_{it} - \left(\hat{\alpha}_i + \hat{\beta}_i R_{mt}\right) \)

Cumulative Abnormal Returns (CARs) are computed by summing $AR_{it}$ over a 21-day event window centred on the insider trading announcement date:

\( CAR_i = \sum_{t=-10}^{+10} AR_{it} \)

We test whether the cross-sectional average $\overline{CAR}$ is statistically different from zero using a $t$-test; a negative $\overline{CAR}$ indicates an adverse market reaction to the announcement.

Data and Sample

Our sample is drawn from the data set used by (Aggarwal et al., 2025). It comprises two types of regulatory actions from 2009 to 2023, restricted to firms listed on the National Stock Exchange (NSE). After removing duplicates and cases with missing stock price data, our final sample contains:

1. SEBI Orders: Final adjudicatory orders; $N = 176$ firm-event pairs.
2. SAT Orders: Appellate Tribunal decisions; $N = 42$ firm-event pairs.

We further look for heterogeneity in market reactions by partitioning the sample along four dimensions of interest:

• Sanction status: Sanctioned ($N = 119$) vs. not sanctioned ($N = 57$). An order may or may not result in a sanction. Here, we examine a reaction based on whether an order resulted in a sanction.

• Violation severity: Major violations ($N = 74$) vs. minor violations ($N = 122$). We classify insider trading violations as Major (e.g., sharing or using unpublished price information for trading) or Minor (e.g., code-of-conduct breaches, delayed disclosures).

• Insider relationship: Connected persons ($N = 44$), deemed connected ($N = 21$), and those with access to UPSI ($N = 19$). Connected persons are loosely defined as those associated with a company (contractual, fiduciary, or employment), while those deemed to be connected persons include their relatives or cohabitants. UPSI access refers to knowledge of information materially impacting the stock price.

• Monetary outflow: Above-median ($N = 59$) vs. at-or-below-median ($N = 60$) alleged illegal gains. Monetary outflow is the total penalty and disgorgement paid to SEBI. We analyze market reaction based on the magnitude of this outflow to see if the amount paid affects the reaction.

Results

Baseline Event-Study Findings

Our event-study results indicate that Indian stock markets exhibit no statistically significant reaction to any type of insider trading enforcement announcement. CARs are indistinguishable from zero across all two regulatory action types at the 95% confidence level, with point estimates close to zero in magnitude. For comparison, SEC insider trading enforcement actions in the US produce average CARs of $-3.47\%$ (Muradoglu and Clark Huskey, 2008).

Figures display the CAR trajectories. In all two cases, the CARs fluctuate around zero with no discernible trend before, during, or after the announcement date.

Cumulative Abnormal Returns (CARs) around SEBI final order announcements ($N = 176$). The shaded region represents the 95% confidence interval.

The result for SEBI final orders is striking: these orders contain explicit findings of misconduct and penalties, yet markets do not react. We discuss two candidate explanations: high appeal and reversal rates, and the small size of monetary penalties in Section Interpreting the results.

Cumulative Abnormal Returns (CARs) around SAT order announcements ($N = 42$). The shaded region represents the 95% confidence interval.

SAT orders, on the other hand, are more final in nature. They may affirm, modify, or overturn SEBI sanctions, and should lead to a market reaction. In our dataset, they also produce no detectable market reaction. However, this result should be interpreted with caution, given the small sample size. With only 42 events, our test has limited statistical power to detect abnormal returns. It is possible that these may be further appealed at the Supreme Court, but given the small sample size, we do not test for the impact of those decisions.

Subsample Analysis

We examine whether the aggregate result masks heterogeneous effects by partitioning the sample along the four dimensions described above. Across all subsample splits, CARs remain statistically and economically insignificant. Even for high-severity cases, directors trading on confidential information, monetary outflows above the median of Rs.~12.83 lakh, and third quartile of Rs.~5.27 crore, abnormal returns remain proximate to zero. Also, there is no evidence of a significant market reaction even in the subsample of cases where the insider relationship is more direct (connected persons). This suggests the null result is not an artefact of averaging across heterogeneous effects; rather, it is pervasive across subgroups.

One caveat to our analysis is if the true information release occurred earlier (e.g., via media leaks), our tests measure the reaction to information from informal sources rather than to the announcement itself.

Interpreting the results

One interpretation of this result is that markets may rationally discount the significance of SEBI enforcement actions. Several institutional features of Indian capital markets lend support to this interpretation:

1. High appeal and reversal rates: (Aggarwal et al., 2025) find that a substantial fraction of SEBI orders (30--41%) are appealed to SAT, and around 50% result in modifications or reversals. Investors who have learned that sanctions are frequently overturned will rationally discount any announced penalty. This is probably compounded by the fact that several SEBI orders are not able to demonstrate the unfair gains or loss avoided, or provide reasons for imposing sanctions as debarment, reducing the credibility of its enforcement actions (Aggarwal et al., 2024).
2. Long enforcement delays: (Damle, 2022) find a median of over three years between violation and SCN, and a further 18 months to a final order. This is reinforced by the findings of (Aggarwal et al., 2025), who find similar timelines for insider trading orders. By the time enforcement is announced, investors may have already moved on.
3. Low penalty amounts: The median penalty is Rs 12.83 lakhs, with approximately 40 cases involving amounts under Rs 10 lakhs. Such low penalties suggest a lower perceived severity of the offense, and consequently signal the market to treat this news as immaterial.
4. Pre-existing credibility discount: If years of weak or delayed sanctions have already led investors to assign a low probability to effective enforcement, individual announcements convey little new information, and markets have stopped paying attention.

Another possibility is that markets receive the enforcement information but do not regard insider trading as material to firm valuation. Under this view, it reflects an investor judgment that insider trading by management is not indicative of broader governance failure or future cash-flow risk.

Conclusion

Indian stock markets exhibit no statistically significant response to insider trading enforcement, in contrast to the negative abnormal returns documented in the US and UK. This result is robust across SEBI final orders and SAT appellate decisions, and persists even for high-severity violations involving senior insiders and large monetary outflows.

The functioning of SEBI entails considerable public expenditure, and the Board has, over time, sought progressively wider powers - including expanded surveillance capabilities. Given this, the question of what is actually being achieved warrants serious scrutiny. A stock price reaction to an enforcement order is one observable signal of whether the market believes the enforcement actions carry some significance. A null result across many orders suggests the market does not view these actions as conveying meaningful new information. It is, therefore, worth questioning if enforcement actions are advancing the goal that justified the expenditure in the first place.

The authors are researchers at Trustbridge Rule of Law Foundation.