MKL
The vultures, activists, are circulating MKL, using short-term issues to advocate change. Specifically, they want the company to sell its non-insurance businesses. (A terrible idea). Anyway, the subs earn around $850 and the activists are valuing that portion at $10 B or a 11.7 multiple.
I would argue that the BRK subs are superior and should be valued higher than MKL. 15x is not unreasonable, which equates to 750 B based on $50 B in earnings.
Like Y, MKL would be a natural fit for BRK.