Savings evidence
Understand exactly what tracked payments establish and what is required to verify realized interchange savings.
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Separate the evidence levels
| Observation | What it proves | What it does not prove |
|---|---|---|
| Invoice imported | The source record is available to inspect. | A correct payment match or eligible card product. |
| Enrichment prepared | The submitted invoice passed preparation checks. | Stripe accepted or transmitted the fields. |
| Payment reported captured | Your authenticated backend reported a capture. | Direct provider verification or enhanced-data qualification. |
| Tracked payment volume | Amount represented by the payment observations in scope. | Actual interchange cost or realized savings. |
| Settlement and qualification evidence | The actual clearing result and network cost, where provided. | A valid counterfactual baseline without further analysis. |
| Verified savings calculation | The defensible difference using evidence, a versioned baseline, and applicable adjustments. | A universal rate reduction on all card payments. |
Establish an eligible opportunity
Enhanced commercial data can affect interchange for eligible business card products, merchant categories, and processor configurations. Visa's Commercial Enhanced Data Program (CEDP) emphasizes data quality; eligibility and the size of the improvement differ by card product and transaction.
- Identify the commercial card product and network, rather than assuming all business payments use eligible cards.
- Confirm the merchant category code (MCC) and configuration accurately describe the business and support the program.
- Check whether the merchant's processor pricing passes through underlying interchange reductions, such as interchange-plus pricing.
- Determine the actual settled qualification category and which higher-cost outcome could legitimately have been avoided.
- Confirm supported clearing fields and authoritative invoice detail without fabricating transaction facts.
A flat-rate processing contract can keep merchant pricing unchanged even when underlying interchange improves. A lower network cost is therefore not automatically a lower merchant cost.
Build a reproducible savings record
- Retain the source invoice version and the documented payment match, including partial allocations where applicable.
- Record the data transformation and processor submission evidence separately from the resulting qualification.
- Obtain actual settlement or network-cost evidence and the relevant fee components.
- Define the counterfactual category and rate methodology for this transaction, holding unrelated processor markup and fees constant.
- Apply the versioned calculation to the evidenced amounts and currency, including applicable program fees.
- Record later refunds, disputes, reversals, or corrections as adjustments with evidence, rather than silently overwriting a savings number.
Use integer minor units for amounts and decimal arithmetic for rate calculations. Preserve the rule version, baseline version, inputs, and rounding policy so a reviewer can reproduce a statement.
Label customer-facing reports precisely
| Metric | Required meaning |
|---|---|
| Reviewed volume | The transactions and period actually included in the review. |
| Eligible commercial-card volume | The subset with supported card, merchant, and processor eligibility. |
| Opportunity estimate | A modeled amount with explicit assumptions and uncertainty; not a realized result. |
| Unable to optimize | Transactions excluded with reasons such as missing data, unmatched invoice, ineligible product, or processor limitations. |
| Verified gross savings | The evidenced reduction against the agreed baseline, before Carden's performance fee. |
| Carden fee | The agreed share of verified savings, with any contractual adjustments. |
| Merchant-retained savings | Verified savings less the applicable Carden fee and relevant agreed adjustments. |
Carden's commercial model is performance-based: a share of verified savings, with no fee when there are no verified savings. The signed agreement determines the methodology and fee schedule; these docs do not substitute an example rate for that agreement.
Questions to ask before approving savings
- Can each amount be traced to source invoices, matched payments, and settlement evidence?
- Is the baseline appropriate for that transaction's card product, merchant, and pricing agreement?
- Are estimated, reported, and verified values clearly separated?
- Are program fees, refunds, disputes, and later adjustments handled consistently?
- Can a second reviewer reproduce the numbers using the stored inputs and rule versions?
If settlement evidence is unavailable, report tracked activity or an explicitly labeled opportunity estimate. Leave verified savings unestablished rather than substituting a fixed assumed interchange improvement.