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What happened

Shares of Norwegian Cruise Line Holdings Ltd (NCLH -0.06%) dropped 15.8% in August, according to data provided by S&P Global Market Intelligence, after the company reported less than stellar results. Investors may be in for a rough year as well.

So what

Second quarter revenue grew 9.3% to $1.2 billion and adjusted net income jumped 12.2% to $192.6 million, or $0.85 per share. But it was guidance that really caught investors off guard. 

Management said it expect adjusted full-year earnings to be $3.35 to $3.45 per share, which is below the $3.72 that analysts were expecting. They also said the $5.00 per share earnings target for 2017 was out the window.

The driver of the disappointing earnings was weak bookings in the cruise market. A falling British pound hurt the company, and business in North America and Europe just wasn't as strong as expected. And customers generally seem less keen on taking Mediterranean cruises right now.

Now what

Sometimes, it's important to put "disappointment" into context. In Norwegian Cruise Line's case, the company expects to earn as much as $3.45 per share this year, which means the stock is trading at just over 10 times annual earnings. And earnings are expected to grow another 15% to 25% next year, so the valuation could still look cheap long-term. I wouldn't be too concerned, but the trends are worth watching. Demand for cruises can ebb and flow, and investors will want to make sure that overall demand continues to climb, because that's what will help drive results for years to come.