Marchionne has been a staunch and ceaseless advocate of the need for consolidation, arguing that the industry needs to amalgamate into larger groups that will share resources and reduce overhead. Under his leadership, the Fiat group consolidated its own operations, and officially merged with Chrysler last year. But he's also been pursuing additional mergers with the likes of Volkswagen, Peugeot, Ford, and Opel (to name just a few).
Now he's pursuing a merger with GM, which has not shown much enthusiasm towards the idea. For one thing, GM is a much larger company, and probably doesn't need FCA as much as FCA needs it. For another, it has a troubled past with Marchionne, who in 2005 dissolved an agreed merger (of sorts) with GM, yet still managed to get the General to pay Fiat some $2 billion in the process.
However, Marchionne is evidently hoping that the intervention of activist investors could compel GM CEO Mary Barra and company to proceed with a merger anyway. For precedent, he's looking at the recent negotiation between GM and some of its stakeholders that prompted the company to buy back $5 billion of its own shares, demonstrating Barra's willingness to deal with investors.
The more compelling precedent, however, may have been set in 2006, when activist investor Kirk Kerkorian locked arms with Carlos Ghosn to get GM to consider joining the alliance between Renault and Nissan. GM ultimately declined, and Ghosn turned instead of Daimler (which of course has its own history of having merged with Chrysler).
Only time will tell if this initiative will prove more successful, but one thing's for sure, and that's that Marchionne isn't about to relent in his pursuit of a major merger partner.