A number of advisers have expressed concern that the long-running stock market rally is tempting 401(k) savers to make withdrawals to spend on nonessentials, which may ultimately prove detrimental to their financial security. "I've seen more money requests for extraneous items in the last six weeks than I have in the last five years," said adviser Jamie Cox of Harris Financial Group.

China's Biel Crystal Manufactory, which makes the glass for screens in most iPhones, has decided to put off a $1.5 billion initial public offering until the third quarter, a source close to the deal said. The strength of the Hong Kong stock market has given the company confidence it has flexibility in timing the IPO and is free to bring it to market when it is in the best interest of the company, the source said.

Americans' personal financial satisfaction increased steadily throughout 2017, reaching a 24-year peak in the fourth quarter, according to the AICPA's Personal Financial Satisfaction Index. Stock market gains were the largest contributor to the increase.

Surveys indicate that millennials might be investing more conservatively than they should be. A Fidelity Investments survey found that 16% of millennials have all their investments in cash, while a LendEDU survey found that 41% of millennials are forgoing investments in the stock market.