Graders — PSA vs BGS vs CGC vs TAG vs AGS vs SGC

What this is: a starting prior for translating gem-grade prices across grading services. PSA 10 is the industry benchmark. BGS 9.5 typically discounts to PSA. CGC and AGS discount further. TAG is the wildcard — growing acceptance, can match or exceed PSA on hot vintage but commonly discounts on modern. Multipliers are conservative defaults — per-card variance is real. Always verify the comp in Price Check before pricing decisions.