Savings evidence
Separate source, preparation, reported payment, settlement, qualification, and verified savings evidence.
On this page
Keep every evidence level distinct
Evidence gets stronger at each verified handoff
A valid invoice or captured report cannot substitute for settlement and baseline evidence.
Available
Invoice facts
Authoritative commercial fields are available for inspection.
Prepared
Transformation evidence
Carden produced provider context from a known invoice revision.
Observed
Payment evidence
The merchant reported authorization, capture, failure, refund, or unknown state.
Settled
Network-cost evidence
Settlement identifies actual clearing outcome, qualification, and cost where provided.
Verified
Savings calculation
Actual cost is compared with an evidenced, versioned counterfactual while unrelated fees stay constant.
| Observation | Establishes | Does not establish |
|---|---|---|
| Invoice imported | Source record is available. | Payment match or card eligibility. |
| Preparation saved | Exact source revision and transformation are retained. | Provider acceptance or network qualification. |
| Payment reported | Authenticated merchant service submitted an observation. | Direct provider verification or interchange cost. |
| Tracked volume | Amount represented by in-scope reports. | Realized savings. |
| Settlement and qualification | Actual clearing result and network cost where available. | A valid counterfactual without further analysis. |
| Verified calculation | Reproducible difference under evidenced baseline and adjustments. | A universal reduction on every commercial card. |
Establish an eligible opportunity
Enhanced commercial data can affect interchange only for eligible card products, merchant categories, geographies, processor configurations, and pricing models. Visa Commercial Enhanced Data Program qualification emphasizes data quality; Mastercard has separate programs and requirements.
As of the September 2026 review, Stripe's payment-line-item guide states that U.S. Visa savings use Product 3 after Visa Level 2 sunset, while Mastercard Level 2 and Level 3 remain separate. Recheck current provider and network requirements at implementation time.
- Identify card product and network.
- Confirm the merchant category accurately describes the business and is eligible.
- Confirm the merchant agreement passes underlying interchange changes through.
- Determine actual settled qualification and the legitimate counterfactual.
- Use authoritative invoice detail and never fabricate required fields.
Square bundled pricing and any flat-rate agreement can keep merchant pricing unchanged even when underlying interchange changes. Lower network cost is not automatically lower merchant cost.
Build a reproducible savings record
- Retain source revision and documented payment match.
- Record transformation and processor-submission evidence separately from qualification.
- Obtain actual settlement and fee evidence.
- Define a transaction-specific counterfactual and hold unrelated markup and fees constant.
- Apply a versioned calculation with decimal arithmetic and documented rounding.
- Record refunds, disputes, reversals, and corrections as append-only adjustments.
Store monetary amounts as integer minor units with currency and rates as decimals. Preserve rule version, baseline version, inputs, source timestamps, and rounding so another reviewer can reproduce the statement.
Label customer-facing metrics precisely
| Metric | Required meaning |
|---|---|
| Reviewed volume | Transactions and period actually included. |
| Eligible commercial-card volume | Subset with supported card, merchant, and processor eligibility. |
| Opportunity estimate | Modeled amount with explicit assumptions and uncertainty. |
| Unable to optimize | Excluded transactions with factual reason. |
| Verified gross savings | Evidenced reduction against agreed baseline before Carden fee. |
| Carden fee | Contractual share of verified savings and adjustments. |
| Merchant-retained savings | Verified savings less applicable fee and agreed adjustments. |
Carden charges only a share of verified savings. The signed agreement defines the methodology and fee schedule; documentation examples never replace that agreement or promise a fixed rate reduction.
Review before approving savings
- Can every amount trace to invoice, match, payment, and settlement evidence?
- Is the baseline appropriate for this card, merchant, processor, and agreement?
- Are estimated, reported, and verified values distinct?
- Are fees, refunds, disputes, and adjustments handled consistently?
- Can a second reviewer reproduce the result from stored inputs and versions?
When settlement evidence is unavailable, label tracked activity or opportunity estimates explicitly and leave verified savings unestablished.