Data semantics and freshness

Two different daily clocks

ETF and on-chain dates are not interchangeable:

Dataset	Date field	Calendar
ETF	trade_date	US ETF trading day
On-chain	metric_date	UTC calendar day

An ETF response's latest date can remain Friday during a weekend or US market holiday. Always label reports using response dates, not the caller's local date.

Settlement

• settled means the ETF observation is eligible for final daily analysis.
• pending means the observation can still be revised.
• /etf/{symbol}/overview uses settled observations only.
• /etf/{symbol}/funds without trade_date selects the latest settled date.
• /etf/{symbol}/daily, and a funds request with an explicit date, can expose pending data.

The ETF collector does not request the still-open New York trading day. Later revisions can nevertheless change a previously collected record.

On-chain completion state

source_eod_completed_at is the end-of-day completion time when known. has_flash_data=true means at least one daily metric is provisional. Use synced_at only as the time the current revision reached the WGO API database; it is not the metric's business date.

Long-term-capital proxy

WGO calculates:

latest cumulative net inflow - oldest cumulative net inflow in the window

The result is classified as increased, decreased, or flat. This proxy is useful for judging whether net subscribed capital has accumulated over a period.

It does not identify investor identity or holding duration. In particular:

• Market makers also participate in ETF creations and redemptions.
• One investor can sell while another buys without changing aggregate shares.
• total_net_assets_change includes BTC/ETH price changes and cannot independently measure new capital.
• Per-fund daily flow does not prove that capital moved directly from one ETF to another.

Numerical representation

Counts are JSON integers. Decimal amounts and ratios are returned as JSON strings to avoid floating-point precision loss. Parse them with a decimal library for financial calculation; do not convert large amounts directly to binary floating point.

Null means that no usable value is available for that field and date. It must not be silently converted to zero.

Collection cadence

Both datasets are collected daily and revisions are synchronized to the API database in short intervals. This is a daily reporting service, not a real-time feed. Consumers should determine freshness from trade_date or metric_date, settlement_status, has_flash_data, and synced_at instead of assuming a fixed arrival time.

The WGO API normalizes and stores daily observations but does not convert them into trade recommendations.