Based on the aggregated intelligence of 170,000-plus investors participating in Motley Fool CAPS, the Fool's free investing community, car sharing network operator Zipcar (Nasdaq: ZIP) has received a distressing two-star ranking.

With that in mind, let's take a closer look at Zipcar's business and see what CAPS investors are saying about the stock right now.

Zipcar facts

Headquarters (Founded) Cambridge, Mass. (2000)
Market Cap $935.9 million
Industry Consumer services
Trailing-12-Month Revenue $202 million
Management

Chairman/CEO Scott Griffith

President/COO Mark Norman

Trailing-12-Month Return on Equity (19.2%)
Cash/Debt $37.8 million / $94.7 million
Competitors Hertz Global Holdings (NYSE: HTZ)

Sources: Capital IQ (a division of Standard & Poor's) and Motley Fool CAPS.

On CAPS, 32% of the 207 members who have rated Zipcar believe the stock will underperform the S&P 500 going forward. These bears include All-Star TSIF, who is ranked in the top 0.1% of our community, and kylehusky.

Earlier this week, TSIF tapped the stock as a questionable long-term opportunity: "I've played ZipCar before, I might get burned for awhile, but competition is growing from rental car companies and the market overall is limited."

Currently, Zipcar even sports a lofty price-to-cash flow of 36.4. That represents a clear premium to listed rival Hertz (3.0), as well as other car rental plays like Avis Budget (Nasdaq: CAR) (1.3) and Dollar Thrifty Automotive (NYSE: DTG) (4.3).

CAPS member kylehusky elaborates on the Zipcar bear case:

The stock is grossly overvalued:
-  Unimpressive financial performance
-  More debt and/or equity financing will likely be needed
-  Business prospects are uncertain
-  Competition is intensifying -- Connect by Hertz is the main threat

Current hype is based on the investors' undue optimism and is predicated on the belief that the ZIP business model is easily scalable and growth will be rapid and substantial. For the reasons stated above I believe this not to be the case.

What do you think about Zipcar, or any other stock for that matter? If you want to retire rich, you need to protect your portfolio from any undue risk. Staying away from dangerous stocks is crucial to securing your financial future, and on Motley Fool CAPS, thousands of investors are working every day to flag them. CAPS is 100% free, so get started!

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. The Motley Fool owns shares of Hertz. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Fool's disclosure policy always gets a perfect score.