Transportation network company Uber has seen tremendous revenue growth in recent years and is valued in private equity markets at more than 60 billion dollars-making it, at least on paper, more valuable than any car company in the world. But the company's growth has not been without controversy and resistance to its business model, which circumvents the regulations effecting traditional taxi companies.The company also faces competition from similar services like Lyft in America and Didi Chuxing in China. The company's CEO Travis Kalanick has managed to raise billions of dollars for the company, from private investors and even the government of Saudi Arabia but it is unclear if the company has managed to turn a profit since it was created. Kalanick has also said he wants to delay Uber's IPO for as long as possible, raising questions about the company's financial fundamentals and its long-term viability.

Uber's biggest potential risk for investors is the resistance its business model has faced by taxi companies and municipal governments. Much of the reason it is able to provide cheaper services than taxi companies is that anyone can be an Uber driver, while taxi company drivers have to go through special training and have special insurance. In some cities, like Austin, Texas, (America's 11th largest city) ride sharing apps have been banned. As the company becomes more widespread, it is almost certain to be subject to greater regulations, making its business model less profitable. Uber's popularity though might meant that any potential regulations passed by city or state governments would be met widespread resistance.

Uber also faces the problem that its services are offered by many competing companies. Its competition, while still smaller, has received significant financial backing. General Motors (GM  ), in a bid to become more than a traditional car company, has invested 500 million in Lyft and Apple (AAPL  ) has invested a billion in Didi Chuxing, a ride-sharing company in China.  In addition to competition, Uber faces the problem that many people in the U.S. do not need the companies services. Car ownership is so widespread in America, many people have no need for the company's app. Pew Research found that only 15% of Americans had heard of Uber.

Uber's long term gambit is a future where people do not own cars, but simply hail them with ride sharing apps whenever they need to get anywhere. The company is also investing heavily in self-driving car technology-currently its biggest headaches are controversies and regulations regarding drivers. But both of these bets are decades from becoming large-scale realities, meaning the company is eventually going to have to go public to raise capital to keep it going. When this happens and the company's financials and practices are subject to greater public scrutiny, the company will probably have to become less aggressive and free-wheeling. Uber has both the potential to be one of the fastest and biggest tech successes and also one of its biggest flops. Uber's future, like all tech companies, depends on the company's continuing ability to grow at an incredible rate. If in the next few years the company hits a wall and its IPO is delayed further, then other ride hailing companies will fill in the gap. The future for Uber is uncertain and when an IPO comes investors need to be very cautious.