Agency Reporting and Fee Structures Explained

Editorial team Spend Ledger

Start with the scope, not the headline fee

An agency quote is difficult to assess until the work behind it is clear. The same fee can cover very different responsibilities: campaign planning, account setup, creative coordination, audience research, optimisation, reporting, billing support or troubleshooting. Some services may be included, while others may be charged separately or handled by the client.

Begin by writing down what the agency will do and what the client will retain. Clarify who creates and owns the advertising account, who controls its permissions, who funds advertising, who approves changes and who is responsible for policy compliance. An account is an operational work tool, not a way to avoid a platform’s rules. If an agency provides access to an account or manages campaigns through its own business structure, the arrangement should be explained and agreed in writing.

Separate the agency’s service fee from the advertising spend. The spend is the amount paid to the advertising platform for delivery; the service fee is compensation for the agency’s work. A quote should make clear whether any other charges apply, such as setup work, creative production, data handling or additional reporting. Ask how taxes, credits, refunds, billing adjustments and account-level charges are treated.

A low fee is not necessarily a low total cost if important work is excluded. A higher fee may also be difficult to justify if the scope is vague. Compare the services, account arrangements, reporting and financial terms together rather than judging a proposal by its headline figure alone.

Percentage-of-spend fees

With a percentage-of-spend model, the agency fee changes with advertising spend. The contract should define the spend base precisely. It might refer to spend recorded by the platform, spend invoiced to the client, or another agreed measure. Those values may not always match, so the parties should specify which source governs the calculation and how adjustments are handled.

For a comparison, define:

• S as the agreed advertising spend for the period.
• p as the agency’s percentage rate.
• F as the agency fee for the period.
• T as the total cost of spend plus the agency fee.

The basic calculation is F = p × S. The combined cost is T = S + F, before any separately agreed charges. To express the fee as a cost per unit of spend, divide the fee by spend: F ÷ S. Under a simple percentage model, that ratio is p.

The arithmetic is straightforward, but the contract details matter. Ask whether the percentage applies to all spend or only to specified campaigns, whether there is a minimum fee, and how the fee behaves if campaigns pause or budgets change. If there is a minimum, the fee may not remain a constant proportion of spend at lower budgets.

A percentage-based fee can make the agency’s compensation rise as spend rises, even if the required workload does not rise in the same way. That does not by itself make the model unsuitable, but it is a reason to agree on what additional work accompanies increased spend. The client should also understand whether the agency has discretion to increase budgets or whether approval is required first.

Flat retainers and performance-linked fees

A flat retainer is a set service fee for a defined scope and period. It does not automatically change with spend. To compare it with a percentage model, define R as the retainer and use S for advertising spend. The retainer’s cost per unit of spend is R ÷ S. As spend changes while the retainer stays fixed, that ratio changes too.

A retainer can make service costs easier to plan, but only if the scope is specific. The agreement should describe the expected work, communication, reporting, approval process and treatment of requests outside the agreed scope. It should also state what happens when campaigns are paused, the workload changes materially or the client asks for work that was not included.

A performance-linked fee depends on an agreed result or measurement. Before accepting this model, define the outcome, attribution method, measurement period and data source. Clarify how cancellations, delayed conversions, duplicate events, tracking gaps and changes to campaign structure affect the calculation. The contract should also explain whether the performance fee replaces a base fee or sits on top of one.

Performance terms can be hard to compare when the result depends on factors beyond the agency’s control, including the client’s offer, website, sales process, inventory or measurement setup. A result-based fee should not imply that an outcome is guaranteed. The parties need a way to review the underlying data and resolve discrepancies without relying solely on a dashboard summary.

For comparison, define P as the performance-linked fee and S as spend. Its cost per unit of spend is P ÷ S, but that ratio may vary as results and spend change. It is therefore useful to inspect the fee under several clearly labelled assumptions about spend and measured performance, without treating those assumptions as forecasts.

Hybrid arrangements and normalising quotes

A hybrid model combines fee elements, commonly a retainer with a percentage of spend or a performance-linked component. Define R as the retainer, p as the percentage rate, S as spend and P as any performance-linked amount. The total agency fee is F = R + (p × S) + P, if all those elements apply. The fee per unit of spend is F ÷ S.

Use the same definitions and the same spend assumption when comparing proposals. For a percentage model, calculate its fee from the agreed rate and assumed spend. For a retainer, divide the retainer by that spend. For a hybrid model, add its fee components first, then divide by spend. For a performance model, use an explicitly stated performance assumption or show the formula without assigning a value.

These calculations do not establish which agency is better. They reveal how the fee behaves at a given assumed level of activity. If two quotes have different scopes, add a scope comparison alongside the arithmetic. For example, note whether each includes account setup, creative coordination, tracking review, campaign monitoring, reporting and client meetings.

It can help to compare proposals across more than one spend scenario, labelling every scenario as an assumption. This shows whether a fixed retainer becomes a smaller share of spend as spend rises, or whether a percentage fee grows with it. Do not treat a model that looks cheaper under one assumption as cheaper in every operating condition.

Ask for a clear worked example using the contract’s variables, not an unexplained total. Confirm whether the example includes platform spend, agency fees and any extra charges. Make sure there is no ambiguity about whether the client pays the platform directly or reimburses the agency.

What reliable reporting should contain

Reporting should let a client understand what was spent, what was changed and what the campaign data can reasonably show. A polished summary can be useful, but it should not replace underlying records or clear definitions. Agree on the reporting schedule, the reporting period, the time zone or date convention used, and the metrics relevant to the campaign objective.

A campaign report should distinguish spend from results and explain how each metric is defined. It should identify which campaigns or account areas are covered, note meaningful changes in delivery and describe material tracking or data limitations. If the report compares periods, the agency should explain any changes in scope, measurement or campaign structure that make a direct comparison less reliable.

Reports should distinguish observed data from interpretation. For instance, a change in a reported outcome may coincide with a budget adjustment, but that alone does not establish why the outcome changed. Agencies can offer analysis, but clients should be able to see the data and assumptions supporting it.

Agree on who will receive reports and whether the client can access the account directly. Direct access helps the client inspect campaign status and platform records, subject to the platform’s permission structure. The agreement should describe the client’s access rights and what happens to those rights if the service ends. Access should be granted through legitimate account permissions, not by sharing credentials in an insecure or unclear way.

Spend reconciliation and raw data

Spend reconciliation checks whether the amounts in agency reports, platform records and invoices refer to the same thing. The agency should identify the source used for reported spend and explain how it handles billing adjustments, credits, refunds, taxes or other differences. The client should be able to trace the reported amount to the relevant account records and billing documentation.

A reconciliation process should also clarify timing. A platform’s reported delivery, an agency invoice and a client’s payment record may reflect different accounting periods or adjustments. The agreement should say how such differences are reviewed and corrected, rather than leaving the client to infer the reason from a total.

Ask what “raw data” means in the agency’s reporting offer. It may refer to downloadable platform data, event-level records, campaign exports or another dataset. The contract should identify what is available, in what format, how often it can be provided and whether it contains personal or otherwise sensitive information. Data access remains subject to applicable platform rules, privacy requirements and the client’s own obligations.

The client should not assume that every report can be recreated from a summary file. Confirm which records remain available through the account, which are supplied by the agency and what happens to working files at the end of the engagement. If an agency manages an account it controls, clarify how the client can obtain relevant campaign and billing records, and what can or cannot be transferred under the platform’s rules.

Change logs, approvals and account arrangements

A change log records material account or campaign changes, such as adjustments to budgets, targeting, creative, bidding or tracking. It should identify what changed and when, and provide enough context for the client to connect the change with later reporting. The parties can agree which routine adjustments need a detailed note and which require advance approval.

Approval rules are especially important where a change could materially alter spend, audience, measurement or policy exposure. Define who may approve changes and how approval is recorded. Also agree how urgent issues are handled. A practical process gives the agency room to manage the work within its mandate while preserving the client’s control over consequential decisions.

Account structure deserves explicit attention. If the client prepares its own account, specify which permissions the agency receives and what work it may perform. If the agency provides or operates through an account under its own business structure, document who owns or controls the account, who is billed, whether the client can access reporting and what happens to campaigns and records if the relationship ends. Do not assume that an agency-provided account can be transferred or that every asset is portable; confirm the actual arrangement and relevant platform rules.

The account must not be used to bypass a suspension, restriction, verification requirement or other platform control. If an account issue arises, the appropriate response is to address its cause and use the platform’s official support or appeal channels. Fee terms should also explain whether work continues while an issue is reviewed, rather than leaving responsibilities uncertain.

A practical review before agreeing

Before accepting a proposal, put the commercial and operational terms side by side. Confirm the scope, fee formula, spend definition, billing flow, reporting contents, raw-data access, change-log practice, approval process and account control. Check how extra work is approved and charged, and what happens when the client pauses activity or ends the engagement.

Use the variables consistently when comparing fees: S for spend, R for a retainer, p for a percentage rate, P for a performance-linked amount and F for the total agency fee. Then calculate F ÷ S under clearly labelled assumptions. This offers a common reference point, not a complete judgement of value. A proposal’s practical cost also depends on the scope, the quality of records and the client’s ability to understand and oversee the work.

Ask for unclear terms to be written plainly. In particular, resolve whether fees are based on spend before or after adjustments, what counts as a performance result, which data source is authoritative, and how account access is handled when the service ends. Current platform requirements and account procedures can change, so verify them through the platform’s own help and policy pages.

A well-defined arrangement makes costs easier to inspect and responsibilities easier to manage. It does not remove uncertainty from advertising performance, nor does a reporting pack prove that every decision was appropriate. The useful standard is transparency: the client can understand what was charged, inspect the relevant account information, see what changed and ask how the agency reached its conclusions.