H&M (HNNMY) stock dropped in the first hour of trading in Stockholm Monday after it announced sales growth in December was slower than expected.

The Swedish fast-fashion retailer said sales in local currencies were up 6%, against analysts's expectations of around 8%. Sales were up 10% when converted in Swedish Kronor, the company said.

H&M stock lost 2.44% in Stockholm to Skr243.90 in the first hour of trading, extending their 52-week decline to to 12.32%. The Stoxx Europe Retail Index lost 1.08% on Monday, having gained only 0.95% in the past year.

The Christmas sales miss follows November figures that showed sales were up 9% in local currency terms but against missed market expectations of a 15% increase.

H&M is facing intense pressure from Zara-owner Inditex (IDEXY) , whose innovative business model have heralded it double-digit sales growth while other retailers flounder.

Inditex stock was marginally down 0.80% in Madrid at €31.68, shares have gained 11.28% in the 52-week period.

Inditex, the world's largest fashion retailer by market value, saw net sales rise by 11% in the nine months between Feb. 1 and Oct. 31 to €16.4 billion ($17.4 billion). In constant-currency terms, top line growth was 15%, "underpinned by solid same-store sales growth," the company said in its earnings released in mid-December.