Merrill Lynch's board of directors has alerted BlackRock chairman Larry Fink that he can take over as CEO if he so choses, CNBC has learned. Fink, according to sources close to the matter, has said he will take the next two weeks to decide. One problem for Fink is his ownership stake in Blackrock, the large money management firm that he founded and is now in a joint venture with Merrill Lynch. Blackrock managed Merrill Lynch's asset management business and Merrill through its brokerage network sells BlackRock mutual funds. But if Fink took over as Merrill CEO, it could be seen as a conflict because Merrill sells BlackRock funds and it is prevented from favoring in-house mutual funds over others when it deals with its brokerage clients. http://www.cnbc.com/id/21627641