Benefits of membership
Business people chatting at a conference

Membership is valuable

COST is the premier state tax organization far and away. It has the size and more importantly talent to make a difference.


COST provides a platform to exchange ideas, form coalitions on critical issues that shape tax policy, and to connect with policy makers across the country.

Which type of membership is right for you?

Corporate Membership

COST membership is exclusive; only multistate businesses that are not engaged in tax advising or consulting may apply for corporate membership. Companies are encouraged to include tax, legal, finance and government affairs in the membership.

Practitioner Connection

Practitioner Connection is a program for law, accounting and consulting firms and service providers to partner with COST.  

Individual Access

Individuals from a member company can sign up to be added to their company membership.  If you are not affiliated with a current member, you will be added to the COST database.