US stocks opened lower Thursday as EU leaders hold a crucial meeting on the eurozone crisis and ahead of a Supreme Court ruling that could strike down key parts of President Barack Obama's healthcare reform.

JPMorgan shares plunged 3.4 percent in early trade on a report that its losses on a mismanaged derivatives trading operation could hit $9 billion, while News Corp shares sank 0.8 percent after it confirmed it would split into two separate businesses.

After 30 minutes of trade, the Dow Jones Industrial Average was down 97.98 points (0.78 percent) at 12,529.03.

The S&P 500 index dropped 8.31 (0.62 percent) to 1,323.54, while the tech-rich Nasdaq lost 21.16 (0.74 percent) to 2,854.16.

Healthcare shares were modestly lower, around 0.5 percent on average, amid mixed expectations for the result of a much-awaited Supreme Court judgment on Obama's landmark reforms.

Pharmaceutical producer Johnson & Johnson was down 0.3 percent while Pfizer lost 0.5 percent.

On the Nasdaq, Google was down 1.1 percent, Microsoft 1.5 percent and Facebook 1.1 percent.

Bond prices pushed higher. The yield on the 10-year Treasury fell to 1.58 percent from 1.62 percent Wednesday, while the 30-year yield fell to 2.66 percent from 2.69 percent.

Bond prices and yields move in opposite directions. - Sapa-AFP