Understand a portfolio XIRR model with your own terminal value
Combine complete recorded external cash flows with your explicitly supplied total terminal value. Read the resulting model separately from verified market performance, and keep unavailable inputs or ambiguous roots visible.
1. Choose the owned portfolio and your terminal assumption
Open Portfolio, select your own portfolio and its Model section. The XIRR panel uses the current admitted ledger revision and complete external-flow table for that portfolio. It does not borrow another account’s records or accept a selected handful of convenient flows. Verify the current portfolio before calculating if its source or account cannot be checked.
Enter your nonnegative total terminal value, including cash, in the portfolio’s base currency. This is your valuation assumption, not a fetched market quote, recorded acquisition cost or verified portfolio value. An explicit zero is valid; a blank field is missing. The field accepts a decimal point, up to 24 integer digits and 18 fractional digits.
Supply an exact valid UTC instant with milliseconds, using YYYY-MM-DDTHH:mm:ss.sssZ, strictly after every recorded external flow. There is no default valuation date. The supported calendar is 2000–2100 and the maximum span is 36,500 days: 100 model years of 365 days, not a promise to accept every hundred-year calendar interval. Then explicitly choose Calculate own model.
2. Read cash-flow direction and numerical availability
Cash contributions have the investor’s negative direction; withdrawals have the positive direction. Your supplied terminal value is the final nonnegative valuation flow. Internal purchases, sales, dividends and fees are not added again as external contributions. Inspect the original flow table, base currency and ledger revision rather than confusing account cash movements with investment performance.
The current model supports base-currency cash flows only, at most 50 complete flows. Foreign-currency cash flows and securities receipts are unsupported, even when another view has a base amount. Missing historical FX or unsupported source widths also refuse calculation. Your terminal assumption cannot repair that history. The application never takes the first 50 rows, guesses a price or truncates money to fit. An unavailable result is never replaced with zero.
The solver uses finite 48-significant-digit numerical precision and an Actual/365 basis. Its disclosed search interval [-30,30] bounds log(1+r), not percentages. Only a unique conventional root becomes an available rate. Multiple or nonconventional roots remain unavailable; detected roots are lower-bound diagnostics. No root within the search interval does not rule out roots elsewhere, and an eight-second timeout does not prove that no root exists.
3. Keep the model separate from actual performance
Read the approximate displayed percentage alongside its original numerical rate and methodology. The raw root is the finite working output, not an infinitely exact real-number solution. It is a model conditioned on your terminal value, not certified market performance, TWR, benchmark comparison or tax output. Realized sale PnL measures a different quantity. Microsoft XIRR documentation explains irregular dated flows and a 365-day basis, but spreadsheet date truncation and its iterative solver differ; no Excel parity or external certification is claimed.
Editing either terminal input conceals the old model and requires another explicit calculation. Account, session, portfolio, visibility or source changes can also hide it or cancel ongoing work. A fresh authority check may readmit the same completed numerical bundle when its exact inputs and recorded flows are unchanged; that check does not silently recalculate a return.
Calculating creates no ledger event, source quote or account-saved XIRR original. The manual-input panel has no file import or export. Use the private investment journal to record your own explanation if needed; it does not attach or certify the computed rate automatically. Local inputs are not a backup and can be lost on reload or leaving their scope. This guide describes application behavior, not editorial approval or investment advice.
4. Use a complete original valuation as the terminal input
In Valuation, prepare the complete single-currency report in the portfolio accounting base currency. Its inline source-terminal XIRR panel can explicitly adopt that whole total, including cash, and its exact economic cutoff. It never substitutes the known portion or cost basis. Review the original source identity and rounding before calculating; a changed original, even with an equal total, requires a new explicit calculation. The separate manual Model section is unchanged.
This uses the exact reported total, including any already disclosed HALF_EVEN rounding to 18 decimal places. It does not round again to fit XIRR limits or move the cutoff to bypass a same-time flow. The complete flows come from the same recorded ledger and applied cutoff, including a custom earlier cutoff. Foreign-currency historical flows, securities receipts, unsupported widths, more than 50 flows and ambiguous numerical roots remain unavailable under the existing rules.
Read this as a model with chosen original source prices. Prices and CNB fixing have their own dates and need not be contemporaneous with the economic cutoff, so this does not establish verified actual portfolio return. The complete model JSON verifies the same ledger, current session and original source download access again, then includes the original valuation, all modeled external flows, terminal input, numerical result and methodology. It omits session and authority-envelope fields and is not an executable worker command or restorable backup. Loss of source access or a changed account hides the model and prevents download.
This is a guide to Datisto. Private features require sign-in and access to your own data. Personal models use your assumptions; availability and permitted use of source data are checked with the particular result. This is not investment advice.