Each company within Chain.io has a random "short code" that is used when you want to participate in sharing with another company.
If you are sharing a trading partner with another company, then they'll need to give you their short code. If they are sharing a trading partner with you, then you'll need to give them your short code.
To find your short code, you must be an Editor or Owner on your account.
1. Click the Company Settings link in the navigation bar
2. Click the Company Profile button
Your short code is in the form on the company profile screen. It is a read-only value that you can copy using the copy button at the end of the field.