“The dominoes are falling. Some of the bubbles have been popped,” Michael Ball, president and lead portfolio manager of Denver-based Weatherstone Capital Management Inc., said by phone. “The market is acting like we’re moving to a phase of a synchronized global bear market,” he said. “We’re like a small boat going through big waves.”

Spiraling losses in tech shares have pushed the Nasdaq Composite Index to the precipice of becoming the first major U.S. stock gauge to enter a bear market since 2009.