Middle-market dealmaking expanded in the third quarter, but the growth slackened in September, according to the Mid-Market M&A Conditions Index (MACI), a barometer created by Mergers & Acquisitions and sponsored by PwC.

The Composite score dropped to 53.8, the lowest since we launched the index in October 2013. The decelerated pace may have been due to seasonal considerations, including parents focused on getting kids back to school. There was no dearth of deals to look at, with Leads holding steady at 62.2. But the score for Signed Letters fell to 53.8 in September from 60.1 in August, suggesting that the slowdown occurred when trying to take leads to the next step.

Completed Deals stalled further, as indicated by the score of 48.4, down from 52.8 in August. The MACI is a diffusion index. Readings above 50 indicate an expansion in M&A activity, and readings below 50 indicate a contradiction.