Advertising rivalry and discretionary disclosure

Advertising is a critical competitive tool that shapes interactions among firms in the product market. Using third-party tracked data on advertising outlet costs, I find that a nontrivial portion of public firms, even those with intense advertising activities, do not disclose advertising expenses in their financial statements, indicating significant disclosure discretion. I further use product category-level advertising data to develop a firm-specific measure of advertising rivalry. I predict and find that advertising rivalry is negatively associated with the likelihood of disclosing advertising expenses. This negative association is more pronounced when firms advertise on less trackable media outlets or have more mature products. These findings suggest that firms consider their advertising expenses proprietary and that concerns about advertising competition discourage the disclosure of advertising expenses.