Here’s a code gist that can be used to update the user’s BuddyPress Extended Profile with additional fields collected at Membership Registration, such as Company.
By default, only the user’s email address, first and last name are added to the xprofile/BuddyPress user meta. This bit of code updates or adds additional Extended Profile (xprofile) fields, allowing you to create a more personalized/customized BuddyPress profile (details on updating the frontend BuddyPress Profile page with these xprofile fields is available here).
If you’ve added custom user fields to your membership site, you can include these fields as well. Just follow the structure outlined in the gist, updating with your field name.