Although subsidiary disclosures in firms’ filings with the Securities and Exchanges Commission (SEC; Exhibit 21) represent the most granular required public disclosure of a firm's geographic footprint, little is understood about the quality of the disclosure, and anecdotal evidence suggests firms may not fully comply with the disclosure requirements. We use data provided by multinational firms to the Internal Revenue Service regarding their foreign subsidiary locations to explore the accuracy of public subsidiary disclosures on Exhibit 21 of Form 10‐K per SEC rules. The overall incidence of nondisclosure is low, suggesting that most firms comply with Exhibit 21 disclosure rules, and that for most applications, Exhibit 21 disclosures provide a reasonable proxy for locations of significant subsidiaries. Nevertheless, there is some evidence of nondisclosure, particularly when subsidiaries are in tax havens, when the firm is more highly scrutinized in the media, or when the firm has other characteristics consistent with low‐quality disclosures such as SEC comment letters.

Drawing on confidential Internal Revenue Service (IRS) data, we examine whether privately held corporations are more aggressive tax planners than their publicly held peers. Contrary to conventional wisdom, we find no consistent evidence that private firms are more aggressive tax planners. We then examine whether private firms’ tax planning differs from that of public firms more generally. We find that private firms engage in more conforming tax planning (planning that also reduces pretax accounting income). However, tests of nonconforming tax planning reveal that private firms generally engage in the same or less planning relative to their public peers. Overall, our findings cast doubt on the belief that private firms are generally more aggressive tax planners than are public firms, but confirm that they engage in more of some forms of general (i.e., conforming) planning. Data Availability: The IRS provided confidential tax information to Michele S. Mullaney pursuant to an Intragovernmental Personnel Act of 1970 (IPA) agreement through the Statistics of Income (SOI) Joint Statistical Research Program (JSRP).