Chad Norfolk, certified financial planner and senior adviser at FAI Wealth Management, is expecting some difficult conversations about portfolio rebalancing with clients over the next two months.
Given the strong stock market this year, many of his clients have accumulated equity positions outside their desired asset allocations and now face the difficult decision of paring back their stock investments and putting the money to work elsewhere.
"It could be really hard for people to do this year," Norfolk said. "Stocks have done great against just about every other asset class. But it's part of the discipline you need in investing."
Mustering the discipline to sell winners and buy losers may seem all the harder given the still-bleak outlook for fixed income investments in a rising interest rate environment.
"Selling high and buying low goes against human nature," said Barry Glassman, president of Glassman Wealth Services. "Whether it is worries about taxes, sentimentality or just inertia, selling something that's done well for you is difficult."
(Read more: It's time for investors to rebalance portfolios)