Inflation and Your Portfolio Even low inflation rates can pose a threat to investment returns. Share | Related Content Bursting the Bubble Tulips were the first, but they won’t be the last. What forms a “bubble” and what causes them to burst? The Anatomy of an Index The S&P 500 represents a large portion of the value of the U.S. equity market, it may be worth understanding. What Is the Dividend Yield? This calculator helps determine your pre-tax and after-tax dividend yield on a particular stock.