How large is the market for the sale of patents? A robust market could be an important way for inventors to realize value from their patents. But while there is strong evidence of a large trade in patents during the 19th century, evidence about the modern trade in patents is more limited. Carlos Serrano uses a new data source to obtain estimates of the market for patents in the US.
The Market for Intellectual Property: Evidence from the Transfer of Patents
By Carlos J. Serrano (University of Toronto)
Full Text
Summary by James Bessen
How important is the market for the sale of patents? Economic historians have shown that during the late 19th century there was a large and robust trade in patents [Khan 2005, Lamoreaux and Sokoloff 1997, 1999]. Scholars have also shown that trade in patent licenses, if not actual transfer of patents, has been important in some modern case studies [Arora et al. 2002]. But there has been little solid evidence about the extent of the modern trade in patents.
This paper by Carlos Serrano uses a new data source to obtain basic empirical facts about that market in the US and it develops an innovative model to estimate the value of that trade.
Data
Patents are not necessarily owned by the inventor, but are typically assigned to an individual or organization when the patent issues. Patents may then be re-assigned to a different owner during the life of the patent. The US Patent and Trademark Office (USPTO) maintains a registry of such re-assignments, which the author obtained for years 1981 through 2002. Some of these re-assignments are made when corporate names change or for other reasons not related to trade. Serrano excludes these, leaving just over a half-million records of patent re-assignments. Re-assignment data do not, of course, capture patent licensing activity nor trade and licensing in technology that does not include patents.
In order to limit his study to ‘small innovators,’ Serrano includes in his data set only patent assignees who obtained 5 or fewer patents per year, studying a total of 453,683 patents for their trading activity. Serrano also studied which of these patents expired for failure to pay renewal fees, which are required to be paid under US law six months before the end of the fourth, eighth and twelfth years in order to keep the patent in force. Using this data, as well as the transfer data, Serrano estimated the patents’ value.
As Serrano notes in his article, not all of these patent re-assignments represent trade in individual patents. Many transfers occur when companies are merged or acquired. The author hopes that by limiting the study to small innovators, more of the activity will represent trade in individual patents. This may mean that estimates of the magnitude of trade are overstated. On the other hand, some patent trades may not be reported to the USPTO, understating the size of trade. Despite these problems, the estimates provide an initial benchmark and the author’s estimates of the value of trade may be robust to these considerations.
Stylized Facts about the Trade in US Patents
Serrano finds that the proportion of patents traded each year starts at about 2.5% and generally drops over time. The exception occurs right after a patent is renewed, when the percentage traded temporarily increases.
Serrano suggests that valuable patents are the most likely to be traded because only these patents have gains from trade that are large enough to offset transaction costs. In general, the value of patents decreases over time with obsolescence, so it is logical that the proportion traded decreases over time. On the other hand, only the more valuable patents are renewed; patents of lesser value do not justify their maintenance fees. This means that the average value of patents in force will increase right after a renewal fee is paid, leading to a temporarily higher rate of trade.
Patents that are cited more frequently by subsequent patents are more likely to be renewed and are also more likely to be traded. This provides some additional support for Serrano’s idea that these are more valuable patents.
Among patents of the same age, those that have been previously traded are more likely to be re-traded and less likely to expire. Again, this supports the idea that these are more valuable patents.
Estimates of Value
Making assumptions about the distribution of patent values, their change over time and the costs of trade, Serrano builds a mathematical model that describes patent owners’ decisions to trade and to renew patents. Then, using his data on transfer and renewal rates, he is able to fit the parameters of the model.
Using these fitted parameters, Serrano makes preliminary estimates of patent value. He estimates that the median value of a freshly-issued patent in his data set is about $21,000 and the mean value is $58,000 (in 2003 dollars). As other researchers have found, the distribution of patent values is highly skewed; there are a few highly valuable patents and numerous low-value ones. Serrano’s mean and median estimates are significantly higher than most of the estimates by researchers who have used European patent renewal data. This is not surprising since the size of the US market is much larger than the markets in individual European countries.
Serrano also estimates the gains from trade. Under some additional assumptions, he finds that about 14% of a patent’s initial value can be attributed to gains from trade. In other words, if there were no trade, patents would be a bit less valuable. Thus, the alienability of patents is a factor in their value even among small innovators, albeit a small part of the total private value realized through patents.
References
Arora, Ashish, Andrea Fosfuri and Alfonso Gambardella (2002), ‘Markets for Technology: The Economics of Innovation and Corporate Strategy.’ Cambridge, Massachusetts: The MIT Press.
Khan, B. Zorina (2005). The Democratization of Invention: Patents and Copyrights in American Economic Development, 1790-1920, Cambridge University Press.
Lamoreaux, N. and Sokoloff, K. (1997). ‘Inventors, Firms, and the Market for
Technology: U.S. Manufacturing in the Late Nineteenth and Early Twentieth
Centuries.’ NBER Working Paper H0098.
Lamoreaux, N. and Sokoloff, K. (1999). ‘Inventive Activity and the Market for
Technology in the United States, 1840-1920.’ NBER Working Paper 7107.
"
Recent Comments