BALTIMORE, United States — Under Armour Inc. suffered its worst stock decline in more than four months after Morgan Stanley pointed to a market-share decline for the company, especially among women.

The company is losing ground to apparel rivals for the first time in three years and average selling prices are falling at an accelerated pace, according to a report from Morgan Stanley analyst Jay Sole.

“Both trends are more pronounced in women’s apparel, despite major marketing investment in this division last year,” said Sole, who cited data from SportScan. He cut his rating on the company to underweight, the equivalent of sell, and lowered his price target to $62 from $103.

The shares fell as much as 10 percent to $67.43 in New York, the biggest intraday drop since Aug. 24. The company had been one of the best performers in the apparel industry, with the stock rising 19 percent in 2015 — its seventh straight year of gains.

By Nick Turner; editor: Mark Schoifet.