MILAN, Italy — Prada SpA, the Milan-based fashion goods maker, dropped the most in 18 months in Hong Kong trading after fourth-quarter earnings disappointed some analysts.

The maker of handbags, shoes and apparel fell as much as 8.5 percent, the biggest drop since Oct. 3, 2011, to HK$70.55, before trading at HK$72.65 at 11:03 a.m. in Hong Kong. The benchmark Hang Seng Index was little changed.

Prada’s same-store sales growth decelerated in the three months ended Jan. 31, mainly because of the later timing of the Chinese New Year in 2013, the designer said in a statement April 5 after the market closed. Margin as measured by earnings before interest and tax widened to 27 percent of sales from 24.6 percent a year earlier, according to the statement.

A “lower-than-expected margin expansion” in the fourth quarter led to operating profit that was below forecasts, analyst Candy Huang, an analyst at Barclays Plc, wrote in a research note dated today. The outlook for sales at stores that have been open at least a year is “moderate,” Huang wrote.

Barclays lowered its rating to equal-weight from overweight.

Net income jumped 45 percent to to 625.7 million euros ($811 million), according to the statement. Fourth-quarter profit gained 37 percent to 217 million euros.

By: Vinicy Chan; Editors: Dave McCombs, Kenneth Maxwell