At least two top-10 Yahoo Inc shareholders are so unhappy with Chief Executive Marissa Mayer’s turnaround efforts that they are making a direct plea to AOL Inc CEO Tim Armstrong to explore a merger and run the combined company. Their move follows an activist campaign by hedge fund Starboard Value LP, which is pushing Yahoo to consider a deal with AOL and unlock Yahoo’s valuable stakes in Asian Web companies. Armstrong has been receptive to these Yahoo shareholders and acknowledged the potential benefits of a deal, the Yahoo investors said.