Tech Investors Anxiously Stand Behind Their Favorites

As Amazon and Alphabet shares fall after a long rally, some say now is the time to buy more

The past week’s 3.8% decline in the Nasdaq Composite Index hasn’t shaken the faith of many investors in technology shares.

When clients call Steven Dudash and ask the Chicago-based financial adviser to sell shares of Amazon.com Inc. and Netflix Inc., he responds this way: “No. I’m going to buy you more.”

Mr. Dudash, whose IHT Wealth Management...