Global markets shuddered on Monday after Greece closed its banks amid fears that the country was headed toward default.

Stocks slumped on Wall Street, after markets in Europe were buffeted by worries that the Greek debt crisis would prove contagious and Chinese investors endured another topsy-turvy session.

The Dow Jones industrial average closed down 2 percent, the Standard & Poor’s 500 was down 2.1 percent, and the Nasdaq fell 2.4 percent. The losses wiped out all the gains for the Dow and S.&P. 500 indexes this year.