Big business CEOs are becoming more optimistic about the prospects for their companies and their workers as Republicans get closer to passing a bill cutting the corporate tax rate.

The Business Roundtable, an influential group of CEOs that has backed the tax cut effort, found in a survey of its members released Tuesday that expectations for sales and plans for investing and hiring are up. An index kept by the group shows those expectations have risen to their highest level in nearly six years.

"The confidence does in part stem from the continued belief that Congress will pass tax reform to make U.S. business more globally competitive," JPMorgan Chase CEO Jamie Dimon, who chairs the group, told reporters.

The group also cited the Trump administration's push to lighten regulatory burdens on business as a reason for enthusiasm.

Executives are also planning for increasing capital expenditures, according to the survey. Dimon attributed that to the expectation that tax reform will pass, and said that wages, not just corporate profits, will rise as a result.

"This will lead to capital expenditures and productivity and wages," Dimon said of the planned business tax reform. "And again, you can't build that into a model because the world is not the same as it was the last time it was done."

"If we don’t have a competitive tax system, we are hurting this country's economics and growth and jobs and wages here," Dimon added. "That’s what we’ve been doing for 10 years.”