Build a ledger-first portfolio product in which every buy, sell, dividend, fee, and currency conversion remains directly editable and exportable. Calculate cost basis and returns from an auditable transaction history, pair them with timestamped market prices, and clearly flag stale or incomplete data. Start with spreadsheet imports and manual entry, then add optional read-only brokerage imports without making account connectivity mandatory.

Recent redesigns of major finance products are replacing or obscuring basic portfolio functions while users still demand fast, deterministic tracking. The resulting switching window favors a focused product built around data ownership, transparent calculations, and interface stability.