Fidelity National Financial, the largest title insurance provider in the U.S., has expanded its investment in LendingTree. Fidelity National purchased another $22 million of stock in LendingTree, bringing its total investment in the Charlotte, NC-based company to 12.4 percent of its voting stock. LendingTree is arguably the most successful of the online mortgage and consumer lending ventures. The firm functions as a broker-like exchange through which consumers find mortgages, home-equity loans, car loans and