01
Transaction source
Shares, prices, fees, sides, dates, currencies, and exchanges come from records the account owner enters or imports.
These records remain the authoritative input for holdings and tax-lot calculations.Know where every number comes from.
Stock Watcher separates user-entered facts, market observations, currency conversion, and calculated portfolio metrics so the meaning and limitations remain visible.
02
Market and benchmark data
Yahoo Finance chart feeds provide demonstration quotes, historical price series, SPY or QQQ benchmark data, news, and market timestamps.
Polling data is not described as exchange-grade streaming or an execution price.03
Currency conversion
Yahoo Finance currency feeds provide FX rates used to normalize totals into the selected display currency.
The interface shows native context, converted values, FX source, and freshness.04
Portfolio calculations
Holdings, fees, realized and unrealized profit or loss, allocations, concentration, and returns are calculated from the ledger.
Tax-lot selection and benchmark choice are explicit account preferences.Data-quality checklist
Before relying on a number, the interface helps you confirm the record and the observation behind it.
- Correct ticker and exchange
- Complete transaction dates and fees
- Native currency preserved
- Quote freshness reviewed
- FX timestamp available
- Partial or stale data warnings resolved
Privacy boundary
Supabase Auth manages passwords. Row Level Security restricts user-owned tables so authenticated users can access only their own records.
Calculation methods
Realized gains support FIFO, LIFO, and HIFO. Time-weighted return reduces the distortion created by deposits and withdrawals.
Provider abstraction
Market access is separated from the product interface so a licensed commercial provider can replace the demonstration feed later.
Frequently asked questions
Clear answers about how this part of Stock Watcher works.
Is the market data real?+
Yes. The demonstration uses current Yahoo Finance chart and currency responses. Freshness varies by exchange, market state, and provider availability.
Why can a displayed price differ from my broker?+
Provider timing, exchange delays, currency conversion, spreads, and the difference between quotes and execution prices can produce differences.
What happens during a provider outage?+
The workspace retains the last successful value when possible, labels stale or partial information, and offers a retry instead of presenting an outage as current data.
Is this tax or investment advice?+
No. The methods are informational estimates for portfolio tracking. Confirm tax treatment and investment decisions with qualified professionals.
Build a portfolio record you can trust.
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