People walk by a Hertz rental car office

Activist investor Carl Icahn Wednesday disclosed a large stake in Hertz and signaled plans to push for a shakeup at the slumping car-rental giant.
Icahn and Icahn-related entities acquired 38.8 million Hertz shares worth $470.5 million, equivalent to about 8.5 percent of the company, according to a securities filing.
The shares were bought "in the belief that they were undervalued," Icahn said.
Icahn plans talks with Hertz management "relating to shareholder value, accounting issues, operational failures, underperformance relative to its peers and (my) lack of confidence in management," the billionaire said.
His group "may also seek shareholder board representation if appropriate."
Icahn's notice came on the heels of Hertz's disclosure late Tuesday that it was abandoning its 2014 profit forecast and that it expects earnings to "be well below the low end of its 2014 guidance," due in part to weakness in the car-rental market.
Hertz also announced a number of personnel changes, including that George Tamke was retiring as the board's independent lead director and that Scott Sider was retiring as group president for the rent-a-car division in the Americas.
In June, Hertz said it would restate its financial results for 2011, 2012 and 2013 after finding accounting mistakes.
A note early Wednesday by Deutsche Bank said it is "difficult to find any positives" in Hertz's securities filing.
Deutsche Bank called the stream of executive departures "unnerving" and said the company's commentary on earnings make it "increasingly clear to us that Hertz is not operating at the same high level that it's closest competitor (Avis) is."
Hertz shares fell as low as $25.75 Wednesday before rallying somewhat on the Icahn news, closing at $30.33, down 3.9 percent.