'Patent trolls' cost other US bodies $29bn last year, says study

The direct cost of actions taken by so-called "patent trolls" totalled $29bn in the US in 2011, according to a study by Boston University.

They include businesses that buy patents with the sole aim of licensing them out, individual inventors, universities and companies that assert patent rights unrelated to the products they make.

"Even so, the direct costs are large relative to total spending on [research and development], which totalled $247bn in 2009, implying that NPE patent assertations effectively impose a significant tax on investment in innovation."