When a purchase follows a chain of referrals, most commission arrangements pay only the last one. The convention is administrative rather than principled, and it shapes the entire referral industry.

The rule is a tracking artefact

Attribution works by recording an identifier when a shopper arrives from a partner and reading it when a purchase completes. Each new arrival overwrites the previous one.

Whichever partner sent the shopper most recently therefore holds the record at the moment of sale, and the payment follows the record.

Nothing in this establishes that the last partner caused the purchase. It establishes only that it was the last one observed before the transaction closed.

Windows determine how long a claim survives

The recorded identifier persists for a defined period, commonly days or weeks, after which no commission is payable on a subsequent purchase.

Longer windows favour partners who create initial awareness, while shorter windows favour those appearing immediately before checkout.

Merchants set the window length knowing this, and it is one of the main levers for shifting payment between different kinds of partner.

The rule creates a race to the checkout

Because only the final position pays, partners are rewarded for appearing as late in the journey as possible rather than for generating interest.

This favours services encountered at the point of purchase over those that introduced the product, and the incentive pushes activity toward the end of the journey.

The result is a concentration of partners competing for the same final moment, which adds little to the merchant while consuming a large share of the commission budget.

Alternative models exist but are rarely used

Distributing commission across several contributing partners is technically possible and better reflects how a purchase actually comes about.

It requires agreement on how to weight each contribution, reconciliation across partners who do not share data, and considerably more administration.

Most programmes conclude that the added complexity is not worth the improved accuracy, and retain the simpler rule with adjustments applied on top.

Adjustments do the real work

Rather than change the model, merchants tune it with differentiated rates by partner type, exclusions for certain traffic, and reduced payments on discounted sales.

These adjustments effectively price each partner's contribution while keeping the single-winner mechanic that makes tracking manageable.

Understanding this explains why partner terms vary so widely for identical placements, and why the headline commission rate rarely describes what is actually paid.