Professional Sports Authenticator (PSA)

parent coCollectors Universe

psacard.com

House Canary

housecanary.com

Longleaf Partners

longleafpartners.com

MPAC

regionCanada

mpac.ca

OPTEON (Apex)

regionAustralia

opteonsolutions.com

Otto & Company

ottoandcompany.com

Pendo Management Group

regionLee's Summit, Missouri

pendomanagement.com

TerraValue

terravalue.net

Topps

regionBrooklyn, New York

topps.com

United States Appraisals

regionOverland Park, Kansas

unitedstatesappraisals.com