Porsche is living dangerously by focusing on its SUVs

Last week, Porsche reported the best financial and sales numbers in company history.

Revenue and profits both surged 25% in 2015.

This week, the company's employees received hefty bonuses as a reward for their hard work.

Porsche sold 225,000 cars worldwide last year - hitting the company's goal of selling 200,000 three year ahead of scheduling.

Although Porsche is best known for its iconic sports cars, the company's two best-selling models are, in fact, the Cayenne and Macan crossover SUVs.

And the company's financial success is built squarely upon the ability to move many examples of those two models.

The two SUVs accounted for 68% of the company's worldwide sales last year. Of the 225,000 cars Porsche sold in 2015, 80,000 were Macans while 73,000 were Cayennes.

The Cayenne has been a sales wonder for more than a decade. However, it was the arrival of the lower-priced Macan in March 2014 that launched the company into the SUV stratosphere. In a matter of months, the Macan went from mysterious new model to the best selling car in the Porsche's stable.

However, an overreliance upon SUVs to carry the sales burden may prove to be a dangerous proposition for Porsche.

In the early 1990s, Porsche's North American sales dwindled to as low as 3,700 a year in 1993. For comparison, Porsche sold a record 52,000 cars last year just in the US.

Porsche's struggles in the early 1990s were due to a poor economy, out-of-date products (968 and 928 models were holdovers from the 1980s) and an over reliance upon a single vehicle - the iconic 911 sports car - for sales.

Porsche learned from their mistakes and fixed their sales problems within a decade by completely revamping their lineup with the new and more diverse models. By 2003, Porsche had two successful sidekicks to the 911 - the Boxster roadster and the Cayenne SUV. By 2010, Porsche added another sports car to its lineup - the Cayman - and the Panamera sedan. But its the Macan's arrival in 2014 that gave the company's its biggest hit.

The Macan has been a dependable source of sales for Porsche. In fact, the company is becoming more and more reliant upon the model.

Times are good right now for SUVs. They are the hottest thing going for everyone in the business. Sedan sales have weakened while formerly SUV-averse carmakers like Lamborghini and Maserati are trying to get one out on the showroom floor.

A solid economy, a pro-SUV consumer base and cheap gas have helped fuel the surge in the demand for SUVs. However, the luxury car market is extraordinarily sensitive to shifts in the economy, with premium SUVs being particularly vulnerable during economy downturns.

With a starting price of just $47,500 (for the 2.0 liter engined version), the Macan will be less susceptible than the majority of Porsche lineup, which lives at a significantly higher price point. The two Porsches most vulnerable in an economic downturn are the Panamera sedan and the Cayenne.

The Panamera and Cayenne's vulnerabilities lie with their higher transaction costs and availability of cheaper alternatives. It an economic downturn, consumers look to downsize. For the Cayenne, it will be the Macan that will likely take many of its sales - similar looks, similar feel, slightly smaller, but considerably cheaper.

The Panamera, too, will be victim to cheaper and smaller high performance sedans. Some of which will be in the form of the A7 from its VW Group stablemate Audi.

The Cayman and Boxster are niche models. Although the duo will take a hit on sales, they are models Porsche doesn't count on to generate volume sales.

That means Porsche will once again depend on a single model to shoulder the weight of the company. This time it'll be the Macan.

But what about the 911? The 911 is an important vehicle. Porsche currently sells 22 different versions of the car. And its iconic status will help it retain much of its sales because if you want a 911, there's simply no substitute. But Porsche doesn't sell enough of the rear-engined sports cars to tip the scale.

And there you have it again. Should the economy take a turn for the worse, Porsche will likely feel the pain once again. The good news is that they have learned and are about as prepared for turbulent times as they have ever been.

But therein lies the bad news. Porsche has done as much as they can in terms of its product lineup to prepare for any bad times that may lie in the future.

When the economy is bad, people tend to buy smaller, cheaper and more fuel efficient. For Porsche, the Macan ticks the boxes about as well as any car they could conceivably build. Porsche is exclusively an upmarket, performance brand. They can't go downmarket in search of sales like Mercedes have with the CLA, Audi with the A3 and BMW with the 2-Series.

And Porsche hasn't hinted that they will be going in that direction. As a result, the automaker seems to have backed itself into a bit of a corner.

With its dependence on a single model to generate volume in an economic downturn, the company lives on a knife's edge. But for Porsche, the Macan is the most capable car the company has ever built to handle the tough times. So it's knife's edge Porsche is happy to dance on.