Here comes Markit services PMI ...

Two key readings on the services sector - the most important sector of the economy - will be released shortly.

First, Markit Economics' final services purchasing manager's index (PMI) is due at 9:45 a.m. ET. The advance reading was 51.3, and it's expected to hold steady in this final report.

The advance release showed that business optimism among service providers, who contribute to two-thirds of economic activity, fell to a record low.

Even as the index remained above 50, in expansionary territory, there was only a marginal increase in service-sector activity.

At 10 a.m. ET, the Institute of Supply Management will release its non-manufacturing PMI, which is forecast at 53.3, up from 52.9 in May.

Refresh this page for updates.

NOW WATCH: GREEN BERET: This is how we're different from US Navy SEALs

Please enable Javascript to watch this video