As the true effects of tax reform unfold, enthusiasm is waning in corporate boardrooms.

That’s the suggestion from a recent survey at BDO USA, which found a distinct drop in the optimism over changes in taw law now that some of the nitty gritty details are coming into focus.

In BDO’s 2018 annual board survey, 61 percent of public company board members said they saw a favorable impact from the Tax Cuts and Jobs Act. While that represents a majority, it’s far less than the 94 percent who expected a favorable impact from tax legislation a year earlier. In the current survey, 39 percent of board members said the tax law had no effect on their business.

Nearly two-thirds of board members, or 64 percent, participating in the survey said their companies are not yet making any changes to their business strategy as a result of tax reform. Among those making plans, 17 percent said they are reinvesting increased capital, 14 percent are raising wages for their employees, and 11 percent are pursuing a merger or acquisition as a result of the tax law.

Enacted in December 2017, the Tax Cuts and Jobs Act took a huge bite out of the corporate income tax rate, reducing it from 35 percent to 21 percent. That provision stoked plenty of optimism over the windfall companies would see as a result of a reduced tax liability.

The law also created a new approach to taxation of income earned outside the United States, however, ending years of protection from tax on foreign profits that companies deemed indefinitely reinvested overseas. It also took away many of the tax benefits associated with executive compensation, especially for performance-based compensation, a common component of any executive pay plan.

While the U.S. Treasury and the Internal Revenue Service have issued some guidance to indicate how they will interpret specific provisions of the massive new tax law, companies are still uncertain about many aspects of the law and how they will be affected going forward. Only 44 percent of board members in BDO’s survey said they had a strong understanding of how their organization’s tax liability is affected by the law and how it affects the company’s tax strategy going forward.

“Getting a grasp on total tax liability is the next great challenge and opportunity for many companies—understanding where tax costs arise across the entire business and developing strategies to minimize their impact on the bottom line,” said Matthew Becker, national tax managing partner at BDO. And tax reform law is just one part of a complex set of tax issues facing companies, he says.