Max Investable Amount (MIA)

The Max Investable Amount (MIA) is the per-SKU (or per-keyword, or per-campaign) ceiling on ad spend, above which each additional euro of spend produces a loss. It is the answer to the question every advertiser must eventually ask: how much can I afford to spend here?

The derivation

For a single SKU:

Max Investable Amount per Sale = ASP × Gross Margin %
Max Investable Amount per Click = Max Investable Amount per Sale × CVR
                                = ASP × Gross Margin % × CVR

Note that this is not the bid — the bid (ASP × CVR × Target ACOS) is intentionally set below the break-even max to lock in operating profit. MIA is the break-even ceiling; Target ACOS is your chosen distance below it.

Per-keyword vs. per-SKU MIA

The same SKU has different MIAs at the keyword level because CVR varies by keyword:

• A branded keyword with 22% CVR has a much higher MIA per click than a generic category keyword at 6% CVR.
• The same bid that is profitable on the branded term is wasted on the generic.

MIA at the keyword level is therefore the disciplined unit of analysis. Setting one account-wide spend cap ignores the fact that some keywords have 4× the MIA of others.

Why MIA matters for budget planning

A common failure: a brand has €50,000/month to spend on Amazon Ads, and assumes the question is "how do I spend €50,000 efficiently?" The MIA framing inverts this:

Total MIA = Σ (per-SKU MIA × addressable demand)

If the aggregated MIA of the catalogue is €32,000/month and the budget is €50,000, the brand is structurally over-budgeted. The last €18,000 will necessarily be spent below break-even. The right question becomes either:

• "How do I expand MIA?" (improve CVR, raise ASP, reduce COGS — raises gross margin).
• "How do I accept a structurally lower planned ACOS for strategic reasons?" (launches, ranking pushes, NTB acquisition).

When spending above MIA is rational

Three legitimate cases:

1. Launch. Buying ranking velocity is buying future organic sales; the marginal ad-driven loss today is the price of the future organic gain.
2. Defence. Letting a competitor own your branded keyword is more expensive than over-bidding to hold it.
3. NTB acquisition. New-to-brand customers carry repeat-purchase value not captured in single-transaction ACOS.

Each of these requires an explicit decision to spend above MIA, with a tracked window after which spend normalises back to MIA.

Common mistakes

• No MIA model at all. Most accounts have a budget number with no derivation. Budget = MIA × strategic multiplier is the correct framing.
• MIA at the account level only. Per-keyword and per-SKU MIA expose 5–10× the variance hidden by the account-level average.
• Treating MIA as static. CVR, ASP, and gross margin all move; MIA recomputes monthly minimum.