Maintain SEO during company acquisition

Hi, I'm looking for some advice on best practice for keeping SEO traffic & keywords from our current website, call it [xyz.com](http://xyz.com) We're in the process of company 2 becoming our parent company, however at the moment are 2 separate companies, 2 separate websites. Eventually, I've been told we'll probably get rid of [xyz.com](http://xyz.com) if this is best practice for SEO. My solution is to set up crucial pages for SEO onto company 2 website, 301 all important pages and set up new pages onto Company 2 website & eventually [xyz.com](http://xyz.com) would becoming redundant. But are there any other options I should be considering?