Six BlackRock executives are in line to replace chief executive officer Larry Fink – who has made no public plans to retire. One of these potential successors, Mark Wiedman, was promoted to a new role last week. This prompted speculation about who could eventually take over for Fink. Depending on how long Fink plans to stay at BlackRock, some top executives may not want to wait for years, one industry observer noted. Larry Fink isn't going anywhere.