In short: in a large account a portfolio is designed around three things that have to coincide: economic goal, sales cycle and currency. One portfolio for every combination with enough volume. Bid limits exist to protect against extremes, not to hold back the target, and migrations are done one campaign at a time, with a log.
In the Intermediate level you learnt what a portfolio is and when to use one. This module starts with the architecture: how the strategies of an account with thirty campaigns, three countries and two currencies are organised, so that Smart Bidding learns properly and the judge (lesson 3) can do its judging.
How do you design a portfolio architecture?
A portfolio groups campaigns that share economics, conversion cycle and, in practice, currency. Crossing the three:
| Criterion | Why it separates |
|---|---|
| Economics (acceptable CPA/ROAS) | One portfolio = one target; different economics demand different targets |
| Conversion cycle | The portfolio is calibrated with one window; mixing 2-day and 40-day cycles confuses the latency |
| Currency / country | A target is a figure in a currency; mixing euros and pesos in one portfolio requires conversion and different thresholds |
| Conversion type | Leads vs sales with a value: different strategies (CPA vs ROAS) |
| Network | Search and Shopping can share a ROAS portfolio if the economics match; Display goes on its own |
Example portfolio architecture in a large account
Account (Spain, EUR)
├─ BRAND portfolio · target impression share, 90% absolute top
├─ CORE ACQUISITION · target CPA €45 (6 generic campaigns, 7-day cycle)
├─ LONG ACQUISITION · target CPA €120 (3 B2B campaigns, 30-day cycle)
├─ HIGH-MARGIN SHOPPING · ROAS 3.5 (high margin)
├─ MID-MARGIN SHOPPING · ROAS 5 (mid margin)
├─ REMARKETING · target CPA €25
└─ LOOSE campaigns · tests, seasonal (no portfolio until there is data)
Account (Mexico, MXN) · the same structure with targets in MXN
Every portfolio with dozens of conversions a month; the campaigns that do not reach that are grouped together until the portfolio does.
What are bid limits for in a portfolio?
In CPC portfolios (and as a ceiling in some Smart Bidding ones), a maximum and a minimum bid. When they make sense:
- Maximum: when an "exciting" auction could cost more than the value of any conversion (protection against extreme cases, not management).
- Minimum: to guarantee presence on brand or in launches where the algorithm still does not estimate well.
When they do not: as a brake on the target. A low maximum limit in a target CPA portfolio stops you bidding hard on the auctions that convert best. If you need tight limits, the target is wrong.
When should you use cross-account bid strategies?
From a manager account you can create portfolios that group campaigns from several accounts: useful for brands with one account per country that share economics and currency, or for agencies with sister accounts. Requirement: the same currency and, sensibly, the same cycle. Upside: learning volume; risk: one target for businesses that may not be as alike as they look.
How do you migrate a campaign between portfolios?
Moving a campaign from one portfolio to another (or from its own strategy into a portfolio) partially resets the learning of both. To keep that to a minimum:
- Move one campaign at a time; do not restructure everything on a Monday.
- Destination target close to the real CPA of the campaign you are moving.
- Wait 2-3 weeks between moves that affect the same portfolio.
- Keep a record: date, origin, destination, reason.
- Better in the low season.
Which architecture mistakes cost the most?
- One portfolio for the whole account (brand subsidising generics).
- Portfolios built around campaign names instead of economics ("everything for Madrid").
- Mixing currencies: a target of 40 works for €40 and for 40 MXN, and Smart Bidding does not know which one it is.
- New campaigns with no data dropped into mature portfolios "so they learn": they distort the portfolio's CPA for weeks.
- Bid limits inherited from the manual era.
- Restructuring portfolios at the same time as changing targets or budgets.
💡 Ninja trick: Smart Bidding (SBNS) reads the account's portfolios and treats their campaigns as a group: it judges compliance using the reference conversions, moves the portfolio's target (not each campaign's) in steps, and shares the budget out between its campaigns. And it has one piece of engineering that this lesson explains: it scales its anomaly thresholds with each account's currency (lesson 6), because a CPA of 1,000 is normal in pesos and absurd in euros.
What you should remember
- Portfolio = shared economics + cycle + currency; one for each combination that has volume.
- Bid limits: protection against extremes, not a brake on the target.
- Cross-account for sister accounts with the same economics and currency.
- Migrate one campaign at a time, with a target close to the real one, and keep a record.