Trading 212 Pies do the fractional-share execution well. The painful step is everything that happens before that: deciding what is in the Pie, deciding the weights, deciding the rebalance rule. That is the part Arithmos replaces.
When the Pie builder alone is enough
- You already know the holdings. "S&P 500 top 10, equal-weighted" is a five-minute job in the Pie builder.
- You want a copy of a popular Pie someone else has shared, no edits.
- You will hold the Pie for years without rebalance changes.
- The thesis fits in a sentence and the names are obvious.
When the Arithmos export wins
- The thesis includes an exclusion. "FTSE 100 ex-tobacco ex-mining" is annoying to construct manually because you have to look up which names sit in those sectors.
- The weighting scheme is not cap or equal. Free-cash-flow yield weighting, inverse-volatility weighting and risk-parity all need the maths done before you start clicking.
- You want a backtest before committing. Pies have no native backtest.
- The screen will be re-run and the Pie re-imported on a schedule. Arithmos keeps the rule; you just import the refreshed file.
- You want a written rationale for every name in the Pie. Useful for ISA portfolios that get reviewed annually with a partner or accountant.
Fees
Trading 212 fees are unchanged either way. There is no spread, no commission and no markup added by Arithmos. We charge the subscription, Trading 212 charges what it always charges.
FAQ
Does the Arithmos Pie export actually load into Trading 212?
Yes. The export uses the Pie JSON shape the Trading 212 importer reads. Create a Pie, paste the file in, holdings and weights come across.
Can I edit the Pie after importing?
Yes. Once it is in Trading 212 it is a normal Pie. You can rename it, adjust weights, add or remove names. Re-importing a refreshed Arithmos file overwrites the holdings; manual edits inside Trading 212 do not carry across the re-import.
