Source: Priceline.

Priceline Group (NASDAQ:BKNG) stock has a taken a considerable hit over the last several days. The online travel agency announced disappointing sales guidance in its latest earnings report, and fears over the impact of the Paris terror attacks are also affecting the stock along with the rest of the travel sector. In all, Priceline is down by nearly 15% in the last couple of weeks. 

However, that's no reason to despair. On the contrary: The recent dip in Priceline looks like a buying opportunity.

Turbulent times for Priceline
Priceline has a big presence in Europe, a key destination for travelers from all over the world. This is a big strategic advantage for the company in the long term, but it's also generating uncertainty and concern among investors right now.

Priceline stock fell by over 4% on Monday as investors reacted with fear following the terrorist attacks in Paris. The company could clearly be affected by lower travel demand in Europe over the coming months, but chances are this will be only a temporary headwind.

The stock was already under pressure before the attacks, though. Priceline reported rock-solid financial performance for the third quarter of 2015, but guidance for the fourth quarter came in below expectations. While the business is still fundamentally very strong, the euro and other international currencies are depreciating against the U.S. dollar, and this is hurting Priceline's performance.

Gross travel bookings were $14.8 billion during the third quarter, a year-over-year increase of 7%. Performance was much stronger when looking at the numbers in currency-adjusted terms, as gross travel bookings grew 22% versus the third quarter in 2014. Priceline's gross profit increased 12% in U.S. dollars and 29% on a constant currency basis during the quarter.

But guidance still came in below expectations. Management is expecting a year-over-year increase in gross profit of between 3% and 10% in the fourth quarter, while constant currency gross profit is expected to grow between 14% and 21%.

Is management being too conservative?
Investment decisions need to be based on forward-looking considerations, not past performance. With this in mind, it makes sense to expect a negative reaction from investors, as the company's guidance was not particularly encouraging.

On the other hand, Priceline's management is well-known for providing conservative guidance numbers, as the company likes to under-promise and over-deliver. Analysts who regularly follow Priceline are well aware of this fact, and they typically project earnings above the company's own guidance. Still, Priceline consistently delivers better numbers than those forecast by Wall Street: The company has beaten analysts' forecasts in each and every quarter since 2011.

If history is any valid guide, management could be keeping expectations low for the coming earnings report, and investors should not be too surprised to see the company outperforming both its own modest guidance and Wall Street forecasts in the fourth quarter of 2015.

Looking at the big picture
It's hard to tell how much of an impact the euro depreciation and global terrorism concerns could have on Priceline's business in the coming months, but the long-term growth story remains pretty much intact. Priceline is the global leader in online travel reservations, an industry offering tremendous room for expansion in the years ahead.

The company's biggest competitor is Expedia (NASDAQ:EXPE), which has a considerable presence in the U.S. However, Priceline is much bigger than Expedia, on a global scale: Priceline's platform has over 820,000 hotels and other accommodations in 220 countries as of the third quarter, a year-over-year increase of 38%. This is a big advantage over Expedia and its global footprint of 270,000 hotels around the world.

Similarly, Priceline produced $3.1 billion in total revenue during the third quarter versus $1.9 billion in sales for Expedia over the same period. Plus, nearly 89% of Priceline's gross bookings come from global markets, while Expedia makes approximately 38% of its business overseas.

Size is a crucial growth driver generating self-sustaining competitive strengths in the business. Hotels and other industry operators need to go with the online travel platform offering access to more customers, and travelers appreciate having plenty of options and conveniently cheap deals. Businesses and customers attract each other to the platform, and bigger platform is a more valuable one. Priceline comes second to none in the industry.

While performance could be hard to predict in the coming months, Priceline is still the global leader in a promising industry, and the company looks as strong as ever from a fundamental point of view. Bottom line: the recent decline in Priceline stock looks like a buying opportunity for investors.