Insurance companies finance a team of private research scientists and engineers to design a deep-space craft to intercept and alter the course of the asteroid, using an impact laser, shaped charges, or whatever method they deem the most successful. During/after the design process the insurance companies will commission a space-transit company (whose "day-to-day" business will most likely be satellite launching for telecom and navigation firms, with the occasional research satellite from universities) to get this craft to orbit and on an intercept course with the asteroid.