Ever since Live Nation, the giant concert promoter, announced a sweeping 10-year deal with Madonna to handle her albums, tours and merchandize, investors have worried that the company spent too much to lure the superstar away from Warner Music Group, Fortune reports.

The stock has fallen roughly 30 percent since the news came out last month.

On Thursday, CEO Michael Rapino and his top executives defended the deal before investors and analysts gathered at the Fillmore New York at Irving Plaza, one of Live Nation's venues.

Judging from the immediate reaction -- the stock closed down slightly Friday -- the Street isn't yet convinced.

The execs didn't offer up exact figures of the deal -- citing a confidentiality agreement with the material girl -- but people familiar with it estimate its value at roughly $100 million for Madonna.

Live Nation (Charts) paid Madonna $25 million in stock as an advance. In addition, according to a person familiar with the terms, Madonna received about $25 million in cash, although Rapino wouldn't confirm this. For each dollar that that comes in, Los Angeles-based Live Nation gets a share and Madonna gets a share that counts against her advance.

Read the full Fortune story .

For reprint and licensing requests for this article, CLICK HERE.