The minimum annual rent of $4 million is $1.4 million greater than what MSG was proposing, said Mangano, and the $195 minimum rent throughout the 34-year lease was more than $80 million than what the county would accrue from MSG, according to the county’s financial adviser, Public Financial Management.

In making its decision, Mangano said his RFP committee studied the two companies' programming, financing and marketing abilities, as well as their past performance, and determined they were “neck and neck.” The decision he said, then “turned to the economic benefit for the county.”

Representatives from Forest City Ratner will join county officials outside the Coliseum on Friday afternoon for a second press conference, at which Mangano said a more specific construction timeline would be revealed.

Bruce Ratner, executive chairman of Forest City Ratner, said he would commit $229 million to his proposed renovations, which would reduce seating in the arena to 13,000 and add an outdoor amphitheater, a movie theater, a bowling alley, a House of Blues or a Filmore Theater, and retail space. The project would take an estimated 15 months.

Ratner’s proposal would bring the New York Islanders to the arena for six games per year, and it would also host Nets practices, boxing, lacrosse, arena football, college basketball and minor league hockey.

Representatives from Forest City Ratner could not be immediately reached for comment.

Mangano said he called both Bruce Ratner and MSG president Hank Ratner — who is of no relation to Bruce — 10 minutes before Thursday’s press conference to inform them of his decision. "I thanked them for their commitment to Nassau County,” Mangano said.