Stocks are back in the red. After falling overnight and early in the day after this weekend's big Greek referendum vote saw Greece reject the latest bailout package from its European creditors, US stocks came all the way back and crossed into positive territory near 11:00 am ET. But at around 1:45 pm ET, the Dow was down 91 points, the S&P 500 was down 13 points, and the Nasdaq was down 33 points. Treasuries were rallying, with the yield on the 10-year note down to around 2.3% from around 2.38% on Friday. Crude oil, meanwhile, was the big loser early on Monday, with West Texas Intermediate crude oil falling as much as 6% to around $53.50 a barrel, the lowest level since early April. In individual stock news, Weight Watchers was soaring, rising as much as 30% after a report in the New York Post said the company could be a takeover target. Last Monday, stocks had one of their worst days of the year following weekend news that Greece would hold a referendum on July 5. That market action, however, saw stocks open lower and then slide throughout the day.Join the conversation about this story » NOW WATCH: 5 scientifically proven ways to make someone fall in love with you