Tiffany & Co (TIF.N) reported lower-than-expected quarterly sales and a surprise drop in comparable sales due to lower spending by tourists and domestic customers in the Americas, its largest market.

The company's shares fell 5.6 per cent to US$87.95 before the bell on Wednesday.

Tiffany, whose one-of-a-kind pieces are a regular feature on Hollywood red carpets, has been struggling to attract young shoppers, particularly in the Americas, as consumers shift to cheaper, chic brands such as Pandora A/S and Alex and Ani.

Comparable-store sales in the Americas, which account for nearly half of Tiffany's revenue, fell 4 per cent, while the company posted a 3-per-cent decline in the Asia-Pacific region in the first quarter due to lower spending by Chinese tourists.

Analysts polled by Consensus Metrix expected a 0.5-per-cent drop in the Americas and a growth of 1.3 per cent in the Asia-Pacific region in the quarter ended April 30.

Worldwide sales at stores established for more than a year fell 3 per cent for the sixth straight quarter, compared with a 1.1-per-cent rise expected by Consensus Metrix.

The company also said it expected its net sales to increase by a low single-digit percentage for the fiscal year ending Jan. 31, 2018.

Excluding a tax benefit of 2 cents per share, Tiffany earned 72 cents, beating analysts' average estimate of 70 cents, according to Thomson Reuters I/B/E/S.

Net sales rose marginally to US$899.6 million in the first quarter, but missed analysts' average estimate of US$913.71 million.

Net income increased to US$92.9 million, or 74 cents per share, from US$87.5 million, or 69 cents per share, a year earlier.