Customize Net Worth Report

When you say "subtotal by company" do you want a subtotal for each bank where you have accounts?

If so, then no, there is no way to make custom groupings of accounts in Quicken. You would have to make a separate report for each bank or export a combined report to Excel and do the subtotaling there.

However there is an existing Idea post on this topic; you can go there to add your comments and and vote for it by clicking on the little up arrow below the vote count. This post has 2 pages of comments; the vote count is at the top of page 1. Ideas need about 50 votes to be considered.