U.S. stock markets started the second half of this year with an encouraging uptick as the outcome of a lengthy rally in last week's summit of European Union leaders held much promise, urging investors to look beyond weak economic readings.  

After an early surge, the Dow Jones Industrial Average fell 45 points to 12,834 by mid-afternoon although the Nasdaq Composite rose 2 points to 2,937. On Friday, the Dow scaled 278 points, or 2.2 percent, closing out June with the largest percentage gain since 1997. Standard & Poor's 500-stock index climbed 2 points, or 0.1 percent, to 1359. The Nasdaq rose 3 percent to close at 2,935.

In spite of a sky-high unemployment rate of 11.1 percent across single-currency euro nations, European markets rose as investors beefed up their holdings in anticipation of further action from EU policy makers. The Stoxx Europe 600 ticked up 1.1 percent on Monday after climbing 2.7 percent on Friday.

Asian markets were mixed because of weak data in China against gains in the U.S. and Europe. Japan's Nikkei Stock Average slid less than 0.1 percent. China's Shanghai Composite went up less than 0.1 percent. India's BSE Sensex ended 31 points down, netting a loss of 0.17 percent.