The S&P 500 has had a remarkable run over the past five months, chalking up a 25% gain. But contrary to feelings that things have risen too quickly, history says that strength begets strength.
Despite the "Magnificent Seven" — or three — powering the S&P 500, the long list of companies hitting new record highs shows another side of the market concentration conversation.
This week saw the stock market's biggest one-day drop — and bounce back. But has anything changed?