Debuting at $18 per share -- more that the expected $14-16 -- ZipCar stock ascended 67% to $30 per share by day's end. The company sold 9.7 million shares and raised $174.3 million. Car-sharing ...

Zipcar's initial public offering (IPO) earlier this month turned a concept – vehicles available for rent by the hour – into a $1.2 billion stock-market value, according to Barron's ...