Indian Securities Regulation and Market Efficiency
Securities and Exchange Board of India (SEBI)
The Securities and Exchange Board of India (SEBI) is the regulatory body for the securities market in India. It is responsible for regulating and supervising the market to ensure its proper functioning. SEBI issues various guidelines periodically to ensure that the market operates in a fair and transparent manner.
Key SEBI Guidelines
- Insider Trading: SEBI has issued guidelines to prevent insider trading. This refers to the practice of buying or selling securities by individuals who have access to non-public, price-sensitive information about an organization.
- Takeover Code: This provides a framework for the acquisition of shares and the control of companies, ensuring transparency during mergers and acquisitions.
- Listing Agreement: SEBI mandates specific rules for companies listed on stock exchanges. These cover financial reporting, shareholder communication, and corporate governance.
- Mutual Funds: Guidelines for mutual funds cover investment restrictions, disclosure requirements, and management fees.
Forms of Market Efficiency
Eugene Fama defined three levels of market efficiency, which have since guided empirical testing in finance:
Weak Form Efficiency
In the Weak Form, current stock prices fully reflect all information contained in historical price sequences. Consequently, abnormal profits cannot be earned by studying past share price behavior or trends.
Semi-Strong Form Efficiency
The Semi-Strong Form suggests that market prices incorporate all publicly available information, including annual reports, news, and media coverage. Most researchers believe U.S. equity markets largely reflect this level of efficiency.
Strong Form Efficiency
This represents the extreme case where stock prices reflect all information, including private or “insider” data. To test this, researchers examine groups with potential access to private information, such as:
- Corporate Insiders
- Stock Exchange Specialists
- Mutual Fund Managers
Empirical Tests of EMH
To determine the degree of efficiency in a stock market, researchers use specific empirical tests.
Tests of Weak Form Efficiency
Weak form efficiency implies that investors cannot use past price history to generate excess profits. If investors knew a price would rise tomorrow, they would bid it up today. Researchers have tested this since the 1950s using two primary approaches:
1. Statistical Tests of Independence
The Efficient Market Hypothesis (EMH) contends that security returns should be independent over time as prices adjust rapidly to new, random information.
- Serial Independence (Autocorrelation): Measures the correlation between returns on day t and previous days. In an efficient market, this correlation should be insignificant.
- Runs Tests: These ignore absolute values and observe only the signs of price changes to determine if sequences are truly random.
- Distribution Pattern: If price changes are random, they should statistically conform to a normal distribution.
2. Tests of Trading Rules
Technical analysts look for consistency in price and volume trends. One common test involves filter rules (e.g., a 20% filter). If a price drops 20% from its peak, it triggers a sell signal. Studies using filters ranging from 1% to 50% have generally found it impossible to earn abnormal returns after transaction costs.
Tests of Semi-Strong and Strong Forms
Semi-Strong Form tests examine how quickly prices reflect public announcements like dividends or bonuses. The fact that money managers frequently use public data to trade suggests the market is not always perfectly semi-strong efficient.
Strong Form tests are categorized into two types:
- Super-strong form: Includes insiders and specialists with monopolistic information.
- Near-strong form: Includes private estimates developed by financial analysts and portfolio managers.