Do patent bubbles exist? Test on innovation situation in China’s A - share market

China’s expanding patent applicants reflects the results of the innovation catch-up strategy, but there have been persistent doubts about patent bubbles. Using SADF, GSADF and BSADF tests, this paper found that the phenomenon of the patent bubble is not common during the observation period in China’s listed companies from 2007 to 2019, and different degrees of patent bubbles occurred only in four industries. China’s technology market is still in the stage of innovation accumulation and catch-up.