Nat. Biotechnol. 28, 557–559 (2010); published online 7 June 2010; corrected after print 13 October 2010

In the version of this article initially published, the authors state: “The patents have been cross-licensed, protecting against unlicensed use of either method. Both the Sakurada and Yamanaka patents are part of the portfolio held by iPierian, a company recently formed by the merger of iZumi Bio, a San Francisco Bay Area biotech and Boston-based Pierian.” This statement is incorrect. The Yamanaka patent (owned by Kyoto University) is not licensed to iPierian. The Sakurada patent (owned by iPierian) is not licensed to Kyoto University. The error has been corrected in the HTML and PDF versions of the article.