Visa (V -0.23%) is leading the Dow Jones Industrial Average (^DJI 0.40%) higher as the financial, health care, and technology sectors all rally today. As of 1:20 p.m. EDT the Dow was up 88 points to 17,065. The S&P 500 (^GSPC 1.02%) was up 15 points to 1,973.

Source: Finviz.com.

There was one U.S. economic release today. The Conference Board reported that its Leading Economic Index rose 0.3% in June. This is a good sign for U.S. economic growth over the next few months.

Source: Conference Board.

The biggest contributor to the Leading Economic Index, by a factor of two, continues to be the difference between long-term and short-term federal interest rates. This is a large contributor, as banks can borrow from the Federal Reserve at the short-term interest rate and buy bonds from the Fed to make a relatively risk-free profit in the short term. So long as the Federal Reserve continues to keep the federal funds rate near zero, this will continue to be the case, though this could change before investors expect. Dan Caplinger, The Motley Fool's director of investment planning, took and in-depth look at June's Leading Economic Index. It should be noted that the index doesn't give us new information; it's only a compilation of economic data.

Yesterday, the stock market experienced its worst loss in three months following the downing of Malaysia Airlines flight MH17 in Ukraine. The stock market has currently recovered half of yesterday's losses, because it doesn't seem there will be much fallout from the attack, as it appears to have been the work of Ukrainian separatists and not Russia. Visa was one of the hardest-hit Dow stocks yesterday, as it has a lot to lose in Russia: The country accounts for 3%-4% of Visa's revenue.

Visa and other payment processors do well as consumers buy more, collecting a small fee with every transaction. With the Leading Economic Index indicating continued growth for the next six months, it's no surprise that Visa is higher today. As the largest and most successful payment processor in the world, having claimed nearly 60% of all card transactions in 2013, Visa has a massive network that provides it with a competitive moat that appears almost unassailable.