Stocks are on a roll, but it might be time for investors to take some profits, one strategist warned.

Liz Ann Sonders, the chief investment strategist of Charles Schwab’s Schwab Center for Financial Research, highlighted what she called “casino-like behavior” among investors as markets climb to new highs. The strategist encouraged investors to rebalance their portfolios to avoid getting caught up in a concentration risk trap.

“I have been very focused on the blurring of the lines between gambling and investing and some of the casino-like behavior that we’re seeing in markets, and there’s no question that there’s speculative juices flowing here,” Sonders said this week.

The S&P 500 recorded its…