CUSIP Regex for Go

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching cusip, ported and verified for Go. Financial data validation has zero tolerance for false negatives — a missed invalid entry can corrupt downstream calculations. The snippet below is ready to drop into your Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

// CUSIP
// ReDoS-safe | RegexVault — Finance > Securities & Trading

package validation

import "regexp"

var cusipRe = regexp.MustCompile(`^[0-9A-Z]{5}[0-9A-Z]{3}[0-9]$`)

func ValidateCusip(s string) bool {
    return cusipRe.MatchString(s)
}

// Example
// fmt.Println(ValidateCusip("037833100")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Securities & Trading category and carries a ReDoS-safe certification. That matters for Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Structure: 6-char issuer code + 2-char issue number + 1 check digit. The issuer code identifies the company; the issue number identifies the specific security class. Check digit uses a weighted Luhn-like algorithm.