Market value and patent citations

• 成果类型: Article
• 署名作者: Hall, BH; Jaffe, A; Trajtenberg, M
• 署名单位: National Bureau of Economic Research; University of California System; University of California Berkeley; Brandeis University; Tel Aviv University
• 刊物名称: RAND JOURNAL OF ECONOMICS
• ISSN/ISSBN: 0741-6261
• 发表日期: 2005
• 页码: 16-38
• 关键词: research-and-development; opportunity; spillovers; INNOVATION; output; panel

摘要

We explore the usefulness of patent citations as a measure of the importance of a firm's patents, as indicated by the stock market valuation of the firm's intangible stock of knowledge. Using patents and citations for 1963-1995, we estimate Tobin's q equations on the ratios of R&D to assets stocks, patents to R&D, and citations to patents. We find that each ratio significantly affects market value, with an extra citation per patent boosting market value by 3%. Further findings indicate that unpredictable citations have a stronger effect than the predictable portion, and that self-citations are more valuable than external citations.