No word yet on all of the specifics, but a source says that the round is similar in size to the recent $41 million raise by rival DraftKings. That deal was done at a pre-money valuation just south of $200 million.

FanDuel previously raised around $18 million from Bullpen Capital, Comcast Ventures, Pentech Ventures, Piton Capital and Scottish Investment Bank.

Both FanDuel and DraftKings provide daily real-money fantasy sports games, with an obvious emphasis on professional football. FanDuel says that it pays out around $310 million to date and that one of its users has won more than $600,000 via the platform.

The real question for both of these sites isn’t user growth, but rather if that growth will cause regulators at the state and/or federal level to reexamine their legality. At issue is whether fantasy sports is a game of skill (legal to wager on via the web) or game of chance (not so much).

FanDuel and DraftKings will argue that they offer games of skill, by pointing to data showing how their best players use statistical analysis to win consistently. Of course, that’s something that some online poker companies also have tried (and failed) to argue. Also will be interesting to see if the NFL formally makes an argument on behalf of the sites, given how fantasy sports has driven increased interest in its league.

Neither FanDuel nor Shamrock responded to requests for comment. A formal announcement could come as early as tomorrow.

UPDATE: FanDuel has just put out a press release. The round amount is $70 million. Shamrock led, joined by NBC Sports Ventures, KKR and existing investors.

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