U.S. CFOs are optimistic about the economy, but they are also concerned that President Trump's "America First" protectionist trade policies would pose a barrier to growth, according to Deloitte's CFO Signals: 2017 1Q report.

"CFOs mostly said they favor liberal trade policy and that more restrictive policy was not likely to spur their domestic hiring," the report said. "Relatively few (CFOs) say substantial trade relationship changes are necessary."

About 40 percent of U.S. CFOs said trade policy has a "substantial impact on their company" (led by retail/wholesale and technology), with 43 percent saying their supply chains "involve substantial international trade, and 30 percent saying they engage in substantial trade in services."

A quarter of respondents said "restrictive trade policy would cause them to reconfigure their supply chains to focus more on the U.S., but relatively few said it would drive more hiring within the U.S." In other words, a border tax would spark the need to find new stateside suppliers but wouldn't necessarily grow revenue or raise demand for new employees.

CFOs ranked Canada, China and Mexico as the top three most important trading partners, with more than 40 percent of them naming each region as important for their company's trading activity.

Despite concerns over trade, CFOs are bullish on the U.S. economy, thanks in part to expectations of lower tax rates and few regulations because of the new administration. The CFO Signals North American optimism index hit a four-year high at 81.85, up from 63.5 the previous quarter and well above the two-year average of 62.5.

"This quarter’s respondents indicated the most positive uptick in sentiment in the seven-year history of this survey," the report says. "And their expectations for growth in revenue, earnings, investment, and hiring all rose and now sit above their two-year averages."

Read more about what U.S. CFOs said about the economy in Deloitte's CFO Signals: 2017 1Q report.