Market Identifier Code (MIC) Regex for PHP

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching market identifier code (mic), ported and verified for PHP. 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 PHP project — whether you're validating in a Laravel validator, a WordPress plugin, or a standalone PHP script.

Php Implementation

<?php
// Market Identifier Code (MIC)
// ReDoS-safe | RegexVault — Finance > Securities & Trading

define('MARKET_IDENTIFIER_CODE_MIC_PATTERN', '/^(?!NYSE$)[A-Z0-9]{4}$/');

function validate_market_identifier_code_mic(string $input): bool {
    return (bool) preg_match(MARKET_IDENTIFIER_CODE_MIC_PATTERN, $input);
}

// Example
var_dump(validate_market_identifier_code_mic("XNYS")); // bool(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 PHP developers because especially relevant in PHP where PCRE backtracking limits can trigger silent failures on malicious input. 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

ISO 10383 MICs: XNYS=NYSE, XNAS=NASDAQ, XLON=LSE, XTKS=TSE Tokyo, XHKG=Hong Kong, XSES=SGX Singapore. The X prefix denotes the primary/regulated market. S prefix for segments.