The S&P 500 is a diversified index, but a mere handful of technology stocks currently have a big influence over its performance.There are 500 companies from 11 sectors represented in the S&P 500, making it the most diversified of the major U.S. stock market indexes.However, the S&P 500 is weighted by market capitalization, which means the largest companies have a greater influence over its performance than the smallest. As of this writing, the following five companies have a combined market cap of $13.4 tri ...