ADP's unchanged margin guide asks little of the business beyond client-fund interest

ADP runs payroll for employers, and between collecting their money and paying it out it holds billions of dollars of client funds, on which it earns interest. In the September 2026 quarter its adjusted EBIT margin, a measure of operating profit that keeps that interest and the cost of the short-term borrowing used to invest it, rose 130 basis points to 26.8%. The company said the quarter beat its own expectations for revenue, margin and earnings per share. It raised its forecast for net client-funds interest for the year by $45 million and lifted its revenue and adjusted EPS outlook, but left its guide for adjusted EBIT margin expansion at 70 to 90 basis points, the range it gave in July.

That combination matters because interest on client money flows almost straight to profit and depends on interest rates and the size of client balances, not on what it costs ADP to run payroll. Set the release's client-funds lines against adjusted EBIT, and about 46% of the quarter's profit increase came from higher net interest, calculated from the reported figures.

The rest of the business still improved. Take that interest out of both profit and revenue and the margin on payroll, HR software and outsourcing rose about 46 basis points from a year earlier rather than 130. That margin is our calculation from the release's lines, not a figure ADP reports. Management pointed to its AI service platform, now used by 60% of service staff against 48% at the end of June, and to a 7% fall in contacts per client among its small-business clients.

Run the same calculation on the full-year guide and the picture changes. At the midpoints of the new ranges for revenue, margin and client-funds interest, the margin outside interest would rise about 8 basis points over the last fiscal year. On the July guide, with less interest expected and slightly lower revenue, the same arithmetic gave about 20. The ranges are wide and the revenue guide is rounded, so the exact figure could sit a little either side, but the direction holds: the extra interest took the place of operating gains inside an unchanged total.

Peter Hadley, the chief financial officer, gave the reason as reinvestment: in AI, products, cloud infrastructure and scaling its offerings for larger and multinational employers. Float and productivity are paying for it, the CFO said, with ADP "dropping some of that fell to the bottom line, putting some of that back into the business for future growth".

There is a plainer reading too. Asked whether conservatism explained the unchanged margin guide, Hadley said it was still early in the year and the first quarter had beaten expectations, so there might be a chance to outperform, but he would not call that out, pointing again to investments ADP wants to make. Either way, the arithmetic for a holder is the same: of the margin gain ADP now guides to, the share that rests on client-funds interest has grown and the share that rests on running the business more cheaply has shrunk.