Despite sanctions and trade embargoes, over the past decade the United States government has granted special licenses allowing American companies to do billions of dollars in business with Iran and other countries blacklisted as state sponsors of terrorism, an examination by The New York Times has found.

At the behest of a host of companies — from Kraft Food and Pepsi to some of the nation’s largest banks — a little-known office of the Treasury Department has made nearly 10,000 exceptions to American sanctions rules, approving deals involving countries that have been cast into economic purgatory, beyond the reach of American business.