LAUSANNE, Switzerland — Chicago has come up with an additional $500 million in private insurance, clearing the way for Mayor Richard M. Daley to sign the host city contract if the city is awarded the 2016 Olympics.

Chicago announced the development Wednesday during a presentation to members of the International Olympic Committee, a key test ahead of the final vote in Copenhagen on Oct. 2.

The IOC is looking for firm financial guarantees from the bid cities, which also include Madrid, Rio de Janeiro and Tokyo.

"Due to the minimal risk in our bid's plan, Chicago 2016 has determined we can provide an additional layer of private insurance to further reduce risk to the City of Chicago and its taxpayers," Lori Healey, president of Chicago 2016, said in a statement.

Unlike the others, Chicago's plan is not underwritten by the federal government. Chicago had previously raised concerns about some of the guarantees required in the standard host city contract, which requires the city to take full financial responsibility for the games.

"This new development will ensure that at the required time — two days prior to the Oct. 2 decision — the Mayor of Chicago will be able to sign the host city agreement," Healey said. "The cost of this solution will be funded entirely by Chicago 2016."

She said the additional $500 million policy brings Chicago's total safety net in public and private funds to $2.5 billion, making the chance of any further liability "extremely remote."

"This is good news for the taxpayers of Chicago," Healey said. "This different approach to our financial guarantees reduces risk to the city, while providing the necessary assurance that the International Olympic Committee has asked for."

IOC president Jacques Rogge said Daley confirmed he would sign the Olympic host city contract without modifications.

"We have only one host city contract," Rogge said. "There is no amendment to the host city contract from the IOC."

Chicago's price tag for the Olympics is $4.8 billion.

Previously, the city's safety net included a $450 million "rainy day fund," as much as $375 million in IOC cancellation insurance, another $500 million in insurance coverage — and a "last-resort" $500 million guarantee of taxpayer money from the city.