[2] The next year, Karnofsky and Hassenfeld formed GiveWell as a nonprofit to provide financial analyst services to donors.

The Hewlett Foundation continued to be a major funder of GiveWell until March 2014, when the Hewlett Foundation announced that it was ending the Nonprofit Marketplace Initiative based on a 2010 study it commissioned that found that only 3% of donors selected charities based on performance metrics (rather than e.g. loyalty, personal connections, or faith), and a subsequent 2012 study showing that efforts to provide better data were not changing that pattern.

[9] In 2013, GiveWell moved its offices to San Francisco where people in Silicon Valley had become strong supporters of the effective altruism philosophy.

[12][13] In 2015, Mike Krieger and his fiancee Kaitlyn Trigger pledged $750,000 to Open Philanthropy over two years, with 10% going to fund the operations of the project.

[14] Open Philanthropy has investigated giving money to criminal justice reform[14] and a range of other policy areas,[15] and has funded work into mitigating risks of artificial intelligence,[16][17][18] biosecurity,[19] and global health.