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Data quality

Snapshots & reconciliation

How Omnicogi validates your transaction ledger against reality — and why it matters.

What is a Snapshot?

A Snapshot is a point-in-time record of what your portfolio actually held on a specific date, taken from your broker's valuation or statement page. It typically takes 60 seconds to add.

A snapshot contains: the date, a list of securities with quantities, and a cash balance.

Snapshots are the only way to "ground truth" your ledger against your actual broker account. Without at least one snapshot, performance metrics are estimates — valid but not validated.

How reconciliation works

When you add a snapshot, Omnicogi runs a reconciliation check:

  1. It replays every transaction in your ledger from the beginning up to the snapshot date.
  2. It computes the implied holdings (quantities per security, cash balance) from the transaction sequence.
  3. It compares the computed holdings against what you entered in the snapshot.
  4. Any discrepancy is surfaced as a reconciliation warning.

A successful reconciliation means your transaction history is complete and consistent with your actual broker account. Your XIRR and TWR can now be marked Reliable.

Common reconciliation mismatches

If the snapshot and ledger don't agree, here are the most common causes:

Missing dividend

Broker CSVs sometimes exclude dividends reinvested in a DRIP (dividend reinvestment plan). Add the dividend manually as a transaction.

Stock split not in CSV

Corporate actions (splits, consolidations, mergers) are often missing from broker export files. Check your broker's corporate actions history and add the event manually.

Transferred holding

If you transferred shares from another broker in-specie (not as a cash sale), the receiving account CSV won't include a "buy" for those shares. Add an opening position transaction.

Fee deducted from cash

Platform fees taken from cash reduce your cash balance. If the CSV omits these, the cash balance in your snapshot won't match.

When to add snapshots

There is no minimum frequency requirement, but we recommend:

  • At least quarterly — add a snapshot at the end of each quarter (31 March, 30 June, 30 September, 31 December) for a clean performance record.
  • After every CSV import — add a snapshot dated as of the last transaction in the imported file to validate the import was complete.
  • At the end of each UK tax year — a 5 April snapshot gives you a clean base for CGT calculations.
XIRR & TWR Next: ISA, SIPP & GIA

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