Twenty years of US nanopatenting: Maintenance renewal scoring as an indicator of patent value

This paper introduces a new measure of patent value – Maintenance Renewal Score (MRSc) – reflecting assignee valuing the patent by paying successive renewal fees. We generate MRSc's for nanotechnology patents issued by the US Patent Office from 1999 through 2009, with US assignees and US inventors. Patenting increases over this period, coincident with increased US funding of nanotechnology R&D. We compare maintenance rates over the period, and against a comparison set of all 1999 USPTO grants to US inventors/assignees. We find differences in propensity to maintain the nanopatents by institution type, technological sector, and patent complexity. •We introduce a new measure of patent quality – Maintenance Renewal Score.•We report differences in propensity to maintain US patents.•The US National Nanotechnology Initiative (NNI) begins in 2003.•US Nanotechnology patenting increases from 1999 to 2009 as NNI takes place.•52.5% of 1999 US patents maintain to full term; 1999–2009 US nanopatents, 40.5%.