Stocks are closing out September with their worst monthly loss since the beginning of the pandemic.

The S&P 500 ended the month down 4.8%, its first monthly drop since January and the biggest since March 2020.

After climbing steadily for much of the year, the stock market became unsettled in recent weeks with the spread of the more contagious delta variant of COVID-19, a sudden spike in long-term bond yields and word that the Federal Reserve may start to unwind its support for the economy.

The S&P 500 fell 1.2% Thursday. It's still up 14.7% for the year.