Reach — the goal where impressions, not orders, are the point.

The default goal of Amazon PPC is orders, and the default success metric is ACOS. Both are right most of the time. But a meaningful minority of campaigns exist for a different reason: to put the ASIN in front of as many shoppers as possible, regardless of whether each impression converts on the spot. Reach as a goal.

When reach is actually the right goal

• Pre-launch warmup. Two weeks before a product becomes orderable, you want the SERP to recognise the ASIN as a candidate for category keywords. Cheap impressions feed the relevance model.
• Seasonal share-of-voice. Black Friday week is not where you teach the auction. You teach it October–November and harvest in late November.
• Brand defence on your own name. Every shopper who types your brand and sees a competitor in slot 1 is leakage. The bid here is priced against the cost of that leakage, not against the immediate order.
• Top-of-funnel for a portfolio. When the first SKU a shopper sees changes which SKU they buy three weeks later, reach on the introductory SKU has value the ACOS report will never capture.

The CPC derivation for reach

For a pure reach goal, the formula collapses to a target CPM (cost per thousand impressions):

max CPC = target CPM × CTR / 1000

If your reach budget tolerates a CPM of €4 and the keyword's CTR for your ASIN is 0.6 %, the maximum CPC that supports the reach goal is €0.67. Any CPC below that means you got the impressions cheap.

The metric you actually watch

For reach campaigns, ACOS is not the success metric.Impression share on the target keyword set is. Watch impression share at top-of-search separately from rest-of-page impression share; reach goals usually only matter for the top.

The trap

Reach goals are a legitimate use of PPC budget, but they are also the easiest place to hide bad campaigns. "It's a brand campaign" becomes a defence for any spend that fails to convert. The discipline: every reach campaign carries a bounded budget, a defined time horizon, and a defined success metric in impression share — not just "raise awareness."