Trade Settlement Date (T+N) Regex for Python

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching trade settlement date (t+n), ported and verified for Python. 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 Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# Trade Settlement Date (T+N)
# ReDoS-safe | RegexVault — Finance > Financial Formats

import re

trade_settlement_date_tn_pattern = re.compile(r'^T\+(?:[0-9]|[1-9][0-9])$')

def validate_trade_settlement_date_tn(value: str) -> bool:
    return bool(trade_settlement_date_tn_pattern.fullmatch(value))

# Example
print(validate_trade_settlement_date_tn("T+0"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Financial Formats category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. 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

T = trade date, N = number of business days for settlement. US equities moved to T+1 in 2024. Most bonds settle T+2. Same-day (T+0) settlement is available for some instruments. T+30 or longer for private markets.