Merrill Lynch & Co.'s bet on Hertz Global Holdings Inc. has more than doubled in value to about $1.5 billion in less than a year, according to Reuters.

Bernstein Research analyst Brad Hintz said the return comes from two special dividends distributed by Hertz and unrealized capital gains from Merrill Lynch's stake in the company, which went public in mid-November.

In December 2005, Hertz was taken private by Merrill Lynch, Clayton Dubilier & Rice and Carlyle Group. Hintz said Merrill initially invested about $748 million in Hertz for a 32.6 percent stake in the company, Reuters reports.

Merrill has since received about $400 million in special dividends, Hintz said. Hertz's IPO was initially valued at $15 per share, giving the company a market value of about $4.8 billion. Hertz shares were trading Monday at $14.99 on the New York Stock Exchange.

The stock closed at $14.75, off 49 cents, or 3.2 percent, according to the Associated Press.

"If one includes the significant residual equity Merrill retains in Hertz following the IPO, its original $748 million investment is now worth about $1.5 billion in cash and stock," Hintz said.

Other analysts say the drop in stock prices could reflect some investors' distaste that management paid themselves the hefty dividend in less than a year, the Associated Press reports.