The U.S. Commerce Department announced Tuesday it would delay its final ruling on anti-dumping rates for Chinese-made hardwood plywood imported to the U.S. until Sept. 5 after two manufacturers identified in the case's related investigation requested a postponement.

The department also added import and export company Jiaxing Gsun to the list of suppliers under investigation, assigning it a 22.14% preliminary duty.

The announcement follows a May 6 hearing, which determined preliminary import tariffs based on weighted averages of alleged dumping margins and set the final ruling for July 17. The moves are part of a two-pronged investigation by the International Trade Commission based on allegations made by a group of domestic manufacturers in September 2012 that Chinese product makers were being subsidized by their government to sell product in the U.S. at below-market rates. The latest preliminary duties join preliminary weighted-average anti-subsidy import tariffs, which also will be reviewed and finalized at the September 5 hearing.