Boeing, Caterpillar and more than 100 other multinational companies in US called on members of Congress on September 26 to reject protectionist legislation against China, in particular pending bills that would impose tariffs against China in retaliation for the undervalued yuan or unsafe imports.

"Imposing unfair barriers to trade in the name of currency valuation or product safety is not a solution to the underlying concerns, and it ultimately undermines the important work that should be undertaken to prepare our economy and our workers for the realities of the global economy," the companies wrote.

A total of 119 companies and 35 industry associations from a range of industries signed the letter. Other companies signing the letter were Citigroup, Exxon Mobil, General Motors and Microsoft.

The letter largely reiterated the position of multinational firms that US competitiveness is helped more by reducing overseas barriers to trade and increasing worker education and training in the US, rather than putting up barriers to trade.

"Conversely, policies that single out individual countries as responsible for the United States' broader concerns will not be effective and should be rejected, as should approaches that violate the United States' own international obligations or that improperly restrict access to the US market," it said. "Doing so can only undermine US credibility and competitiveness and put US exports at substantial risk of retaliatory action."

The letter comes as companies anticipate that Congress will take up a China currency bill sometime in the fall. Two Senate committees have approved different bills on this topic, including one that would allow tariffs on Chinese imports to increase after a formal finding that the yuan is undervalued.

However, the Senate is expected to wait for action in the House before moving for a full vote. Key members of the House Ways and Means Committee are expected in the coming weeks to introduce their own version of a currency bill and hope to get it approved in the coming months.

Congressional and industry sources said earlier this month that a crowded legislative calendar could push off further consideration of these bills until next year.