Done by its own staffers

• Not outsourced
• Employed around head office, not contracted out
• Like many company publications
• Done by its own staff
• Limited to an organization
• Originating within a company
• Like company newsletters
• Not contracted out, say

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
also in-house , 1955, from in + house .

Wiktionary Word definitions in Wiktionary
a. (alternative spelling of in-house English)