Pro-Rubio nonprofit group has raised more than $15 million

Washington (CNN)The nonprofit group backing Florida Sen. Marco Rubio's bid for the White House has raised nearly $16 million, the organization announced Monday.

The Conservative Solutions Project, which as a tax-exempt organization is not required to disclose its donors, said those contributors have given them $15.8 million. The super PAC associated with that nonprofit -- Conservative Solutions PAC, which must name its backers and their donations -- will have to release its totals by the end of the month.
Though political nonprofits can shield the names of their donors, they are limited in the amount of money they can spend advocating for the election or defeat of candidates. The group's first television advertisement praised Rubio's leadership on negotiations with Iran, but did not directly call for him to win the GOP nomination.
    The nonprofit group said Monday that it would boost the size of that advertising campaign to $3.3 million, having spent $1 million in its first week. The organization said it has now raised two-thirds of the money it hopes to over the course of the campaign.
    Allies of other candidates, like Jeb Bush, have recently set up similar nonprofit organizations to bolster their political operations, while some other Republican rivals used their older groups to serve as de facto campaigns prior to their kickoff events.