More than 300 companies are talking to government officials in Washington this month about how detrimental the trade war between the U.S. and China has been and will be to their business.

Testifying in front of the Office of the U.S. Trade Representative, major U.S. companies including Best Buy, HP and Hallmark Cards are voicing concerns about how the additional tariffs that President Donald Trump threatened to slap on China would impact their businesses and cause them to lose business to foreign competitors.