MADRID (Reuters) -Blackstone's Spanish gambling company Cirsa opened its initial public offering to investors on Wednesday and will close it on July 7, a bookrunner said in a document seen by Reuters.

The new shares in the company would be allocated to investors on July 7 and would start trading on the Spanish stock market on July 9.

Cirsa seeks a valuation of 2.52 billion euros ($2.97 billion) in the IPO, it said on Monday.

The casino operator expects the operation to be worth between 453 million euros and 521 million euros, including a so-called greenshoe option that allows it to float more shares if demand is strong enough and a secondary sale by existing shareholders, the bookrunner said.

Bookrunners for the IPO include BBVA, Jefferies, Mediobanca, Societe Generale and UBS.

Cirsa is controlled by U.S. private equity fund Blackstone and operates casinos and gambling platforms in Spain, where it is the largest casino operator, Italy, Morocco, as well as in Latin America. It entered Portugal and Puerto Rico last year.

The IPO would be the first in Spain since travel tech company HBX Group raised 725 million euros in February in a deal that valued it at 2.84 billion euros at the time.

($1 = 0.8491 euros)