Wall Street's main indexes opened lower on Monday as Treasury yields rose after Moody's downgraded the U.S. sovereign rating, sharpening focus on its mounting debt. The Dow Jones Industrial Average fell 111.

Markets rallied last week, but Moody’s U.S. credit downgrade, rising bond yields, and tariff concerns now pressure equities. Retail earnings and sentiment data loom large.

Stocks slumped at the open of trading on Monday after a downgrade of U.S. credit triggered a spike in debt yields that threatened to raise borrowing costs throughout the nation's economy. The Dow Jones Industrial Average dropped 295 points, or 0.7%, while the S &P 500 fell 0.9%. The tech-heavy Nasdaq plunged 1.2%.