Stocks finished lower on Tuesday as a run of downbeat economic data pressured markets on the week's second trading day.

When the closing bell rang on Wall Street, the S&P 500 was down 0.2%, the Dow off 0.5%, and the Nasdaq was unchanged, falling 0.27 points, or 0.00%.

All three major indexes suffered losses to start the week, with the S&P 500 falling by the most since June 16 while the Nasdaq dropped some 2.6% on Monday. The tech index is closed Monday's session down about 6% from its most recent high after a 25% rally from mid-June to mid-August.

A busy week for economic data got underway in earnest Tuesday morning, with the preliminary August reading on service sector and manufacturing activity from S&P Global showing a further decline in business activity in the private sector this month.

The report showed service sector activity fell to 44.1, a 27-month low and down from 47.3 the prior month and below the 49.8 that was expected. Any reading below 50 shows contraction in the sector. Manufacturing activity, meanwhile, stayed in modest expansion territory, with the index hitting 51.3, down from 52.2 in July.

Excluding the drop in this index seen between March and May 2020 when the pandemic rocked the global economy, Tuesday's data signaled the sharpest decline in output in 13 years.

"August flash PMI data signaled further disconcerting signs for the health of the US private sector," Siân Jones, senior economist at S&P Global Market Intelligence, said in a statement on Tuesday. "Demand conditions were dampened again, sparked by the impact of interest rate hikes and strong inflationary pressures on customer spending, which weighed on activity. Gathering clouds spread across the private sector as services new orders returned to contractionary territory, mirroring the subdued demand conditions seen at their manufacturing counterparts."

At 10:00 a.m. ET, reports on new home sales and the Richmond Fed's manufacturing index were released and both missed consensus expectations.