Free ETF NAV API
Sources, Fields & Python

Free ETF NAV API: what developers actually need

ETF NAV data API fields to verify

NAV is the per-share value of the fund's net assets at a stated valuation time. An ETF's market price can trade above or below that value, so a generic quote endpoint is not automatically an ETF net asset value API. The U.S. SEC Investor.gov definition of NAV is a useful baseline.

The valuation clock matters as much as the number. Official NAV may use closing prices, fair-value adjustments, accrued income and expenses, liabilities, and an official shares-outstanding figure. For international or multi-asset funds, some underlying markets may already be closed when the ETF still trades, so a same-screen comparison can combine observations from different economic times.

Free ETF NAV API sources to evaluate

Evaluate each source with an ordinary domestic equity ETF, an international ETF whose underlying market closes earlier, a bond fund, a distribution date, a split or share-class event, and a market holiday. Compare value, valuation and publication times, currency, status, revision behavior, and identifier resolution rather than asking only whether a field named nav exists.

How to integrate a free historical ETF NAV API

Keep the provider-specific field mapping outside the calculation. After normalizing a response to the keys used below, this example validates the official NAV observation and calculates a premium or discount only when listing, share class, and currency match.

from datetime import datetime
from decimal import Decimal, InvalidOperation

import requests


def parse_time(value: str) -> datetime:
    parsed = datetime.fromisoformat(value.replace("Z", "+00:00"))
    if parsed.tzinfo is None:
        raise ValueError("timestamps must include a timezone")
    return parsed


def fetch_json(endpoint: str, params: dict, headers: dict) -> dict:
    response = requests.get(
        endpoint, params=params, headers=headers, timeout=(5, 20)
    )
    response.raise_for_status()
    return response.json()


def premium_discount(nav_row: dict, price_row: dict) -> dict:
    identity = ("fund_id", "share_class", "currency")
    if any(nav_row.get(key) != price_row.get(key) for key in identity):
        raise ValueError("NAV and price identity or currency mismatch")
    if nav_row.get("nav_type") != "official":
        raise ValueError("premium calculation requires official NAV")
    try:
        nav = Decimal(str(nav_row["nav_per_share"]))
        price = Decimal(str(price_row["price"]))
    except (KeyError, InvalidOperation) as exc:
        raise ValueError("invalid NAV or price") from exc
    if nav <= 0 or price <= 0:
        raise ValueError("NAV and price must be positive")

    nav_time = parse_time(nav_row["valuation_time"])
    price_time = parse_time(price_row["observed_at"])
    gap_minutes = abs((price_time - nav_time).total_seconds()) / 60
    return {
        "premium_discount_pct": ((price - nav) / nav) * Decimal("100"),
        "nav_time": nav_time,
        "price_time": price_time,
        "time_gap_minutes": Decimal(str(gap_minutes)),
        "comparison_is_stale": gap_minutes > 60,
    }

Use QVeris to find and call ETF NAV capabilities

• Open the QVeris provider details for relevant ETF or fund-data capabilities.
• Inspect input and output schemas, NAV type, currency, valuation policy, publication time, revision state, and license before letting an agent call a capability.
• Require an explicit fund and share-class identifier, date range, official versus indicative NAV, and freshness tolerance in every tool request.
• Preserve the provider, raw value, identifier, valuation and publication dates, revision, and validation result with every downstream use.

Free ETF NAV API FAQ

Authoritative references and related guides