Stocks sank Thursday to give back gains after a record-setting session, with investors nervously eyeing signs that the economic recovery might get derailed, Yahoo Finance reported. 

The S&P 500, Dow and Nasdaq were each off by more than 1% before paring some losses marking the first time since June that the S&P 500 opened more than 1% lower. A day earlier, the blue-chip index rose to a record closing high for the eighth time in the last nine sessions as concerns over a near-term monetary policy adjustment and sustainably high inflation abated. The Dow, which is heavy in cyclical and value stocks that stand to benefit from a strong economic recovery, underperformed against those the other two major indexes.

The benchmark 10-year Treasury yield sank further to hover around 1.29%, with the dip in rates reflecting both easing inflation expectations but also uncertainty over the sustainability over the recovery. Concerns over the global recovery also increased after Japan proposed re-instituting a state of emergency ahead of the Tokyo Olympics due to recent COVID-19 surges. 

"People have. some concerns about how the Delta variant is going to play out in the economy, and we don't know what's going to happen to the spending with consumers once unemployment benefits run out in the September time frame," Julie Biel, Kayne Anderson Rudnick portfolio manager, told Yahoo Finance on Thursday. "I think there's a lot of uncertainty, and how I would characterize this rally is, it is kind of a cynical rally, where people don't necessarily feel as strongly about the economy, but they feel they have to stay invested. And so I think the fact that it is in this mindset means that it could pull back very quickly. So I would expect more volatility going forward." 

Recent data on the economic recovery has been mixed, with job openings rising to yet another record high in May and labor scarcities curbing the pace of the rebound across industries. Thursday's jobless claims report showed new weekly filings unexpectedly increased, with the number of new filers and total claimants still highly elevated compared to pre-pandemic levels. 

(With input from agencies)