Low Beta Is Not Low Risk: Evidence and Investor Implications from Five Indian Pharmaceutical Stocks, 2021–2025

Abstract

Pharmaceutical stocks are often called defensive, but “low risk” can mean a modest response to market swings, low volatility, or protection of capital when markets fall – three different claims. This study separates them for five Indian pharmaceutical companies (Sun Pharma, Cipla, Dr. Reddy's, Zydus and Lupin) over four fiscal years, April 2021–March 2025. Before analysis, the price data was audited against official exchange records, which uncovered a two-year benchmark-duplication error in the Sun Pharma series, an unadjusted Dr. Reddy's stock split, and an unbridged Zydus ticker change – all corrected using official NSE and BSE sources. Using ordinary least-squares regression, correlation and descriptive statistics, all five stocks show a market beta below one against BSE SENSEX 50 (0.31–0.67), yet every stock is more volatile (20.8%–28.1% a year) than the index (13.8%), and four of five lost more than a quarter of their value at some point. An equal-weight portfolio has a beta of 0.54, but its maximum drawdown (26.0%) exceeds the index's (17.1%) and stays negative on 88% of the market's fifty worst days despite losing less than the index on average. An 80/20 index–pharma blend lowers historical variance by about 12%, stable across sub-periods, though its own drawdown is marginally deeper than the index's. Repeating the analysis on the uncorrected data reverses the headline beta finding, showing that data verification mattered more than any statistical technique here. Beyond this sample, the paper documents a reproducible data-integrity case and translates its findings into guidance for retail investors, advisers, fund managers and investor-education policy on what a “defensive” label can and cannot support.