Let’s hear it for the index. Big-cap U.S. index mutual funds topped performance in November among funds with the most assets. Vanguard Total Stock Market Index Fund , with $36.98 billion in assets, climbed 2.41% last month, according to Lipper Inc. data. The fund tracks the broad stock market, with about 71% of its assets in large- and megacap stocks, 19% in midcap stocks and 9% in small- and microcap stocks.