Zaldokas discusses how TV advertising affects real time investor behavior


Amid the turbulence in stock markets, retail investors continue to look for investment ideas. Investors could even be inspired by ads they see on TV. Alminas Zaldokas, Assistant Professor of Finance at HKUST and IEMS faculty associate, found a predictable, recurring, and robust pattern between investor exposure to television commercials and subsequent retail stock trading in a recent paper. Within 15 minutes of seeing an ad for a firm’s product or service, investors begin searching for financial information on that firm’s stock. This surge of attention leads to a higher trading volume of the advertiser’s stock the following day and contributes to a temporary rise in the stock price of that firm. Indeed, Zaldokas’s research shows that the effects of advertising on investor behavior and stock prices are more far reaching than previously believed. His research finds that Within 15 minutes, an average TV ad spurred an immediate 3% increase in queries of U.S. Securities and Exchange Commission. Google searches for related financial information immediately climbed by 8%. Investors also sought information on the advertising firm’s closest rivals and their suppliers. These ad-driven information searches on the closest rivals translated to higher trading volume of their stocks, too. Zaldokas believed his work is the first to document a causal effect of a given firm’s ads on investor interest in its closest rivals and major suppliers.

Read his blog post published on 15 May on Columbia Law School's Blue Sky Blog.

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