Bursting the Bubble Tulips were the first, but they won’t be the last. What forms a “bubble” and what causes them to burst? Share | Have A Question About This Topic? Name Email Address Question Thank you! Oops! Related Contents Inflation and Your Portfolio Even low inflation rates can pose a threat to investment returns. Rebalancing Your Portfolio Over time, different investments' performances can shift a portfolio’s intent and risk profile. Rebalancing may be critical. Keys to Investing for Retirement There are some key concepts to understand when investing for retirement.