MasterCard isn't the only payment network that was popular last quarter. No. 1 network Visa ( V) also generated substantial buying pressure from institutional investors. All told, institutions picked up 14.5 million shares of the firm, including Farallon Capital Management, which increased its position in the stock by 1.3 million shares in the third quarter. The stock is also one of Warren Buffett's 6 New Investments. Visa's top-dog status is significant for investors. The firm's logo graces around 60% of the world's credit and debit cards, providing the firm with a massive share of a growth market. That scale adds significant value to Visa's network as well; its popularity makes it a necessity for merchants to accept, and that universal acceptance makes the card even more popular. The challenges of replicating that network give Visa a major edge over new potential rivals. Investors should like the fact that, like MasterCard, Visa is primarily a tech stock. The firm doesn't carry credit risk on its balance sheet because it relies on financial firms to actually issue cards. Instead, growing dollar volume of card transactions (including debit transactions) stands to grow Visa's top line. Visa shows up on recent lists of 7 Best Long-Term Stock Picks by Morgan Stanley and 6 Slam-Dunk Stocks for 2012 and Beyond.