After retrenchment in the last two months, the short-term and mid-term ACIs shot up by more than two points each, both driven by extremely strong rises in our panelists' predictions for growth at their large-business clients.

The ACI, published in partnership with ADP, is a monthly economic indicator that leverages the insights of accountants into the strength and prospects of businesses in the U.S. The 3-Month ACI came in at 53.71, up from last month's 51.1. The 6-Month ACI, meanwhile, hit 56.21, from last month's 54.07.

Low oil prices and a generally rosier economic picture no doubt helped boost expectations for business clients of all sizes; interestingly, respondents were least optimistic about growth at their own firms.

The ACI is created from a monthly poll of the Accounting Today Executive Research Council, an online community of more than 1,500 tax and accounting professionals.