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 Message Thank you! Oops! Related Content Inflation and Your Portfolio Even low inflation rates can pose a threat to investment returns. Mutual Funds vs. ETFs Exchange-traded funds have some things in common with mutual funds, but there are differences, too. 5 Smart Investing Principles Principles that can help create a portfolio designed to pursue investment goals.