Reuters is reporting that Iran has been making secret oil sales to China and South Korea by switching off ship transponders normally required to be on by international maritime law.
The report says that the National Iranian Transport Co, NITC, ordered most Iranian supertankers to turn off and conceal their transponders in an effort to hide global oil sales before the pending July 1 deadline in which an EU ban on Iranian oil takes effect. The buyers of the oil have requested this in an effort to avoid US sanctions which ban companies buying Iranian oil from doing business in the US or using the US financial system.
Most of the floating oil reserves Iran held have not disappeared also, and speculation is growing that Iran has given generous credit terms and financing terms to China's oil importers as well as some Indian importers.
Read the whole story: http://www.reuters.com/article/2012/04/13/us-iran-oil-tracking-idUSBRE83C0TS20120413