Oil on Monday dropped from its 7-month high to hover around $68. The U.S. dollar extended gains after its largest 1-day rise in five months on Friday. And the 10-year U.S. Treasury yield hit a 7-month high on Monday ahead of auctions this week, amid speculation the Federal Reserve may hike interest rates sooner than expected.

Art Cashin, UBS Financial Services director of floor operations, offered CNBC his market insights for Monday.