# Proportional minimum-commit allocation > Source-anchored research for Proportional minimum-commit allocation. Run status: COMPLETED. Parent: [Atlas Cost Commitments, Cross-Org Billing and FinOps Tooling](https://llms-explorer.com/tree/atlas-cost-commitments-cross-org-billing-and-finops-tooling/) · 4 facets · 15 facts · page: https://llms-explorer.com/tree/proportional-minimum-commit-allocation/ ## How it works - Derived model for MongoDB's example: shortfall S=max(0,M-sum(u)); allocated shortfall a_i=S*u_i/sum(u), when sum(u)>0. Here u is subscription-uplift charges; the example does not establish a universal denominator for every contract. (low confidence) (verified as of 2026-10-30) — [source](https://www.mongodb.com/docs/atlas/billing/) - Atlas invoice charts omit monthly and flex-commitment shortfalls. Coincident daily uplift and month-end minimum charges can trigger daily maximum billing alerts. (low confidence) (verified as of 2026-10-30) — [source](https://www.mongodb.com/docs/atlas/billing/) ## Measurements and reference values - Finout documents telemetry-based allocation using indicators such as transmitted bytes or query length, and customized allocation percentages covering 100% of a shared pool. It states that virtual tags with reallocation are absent from raw data. (low confidence) (verified as of 2026-10-30) — [source](https://docs.finout.io/user-guide/inform/shared-cost-reallocation) ## Problems, failure modes and limitations - Atlas Total Usage and By Deployment invoice charts exclude monthly and flex commitment shortfalls. Consequently, those charts alone cannot reconcile the full amount due when a shortfall exists. (low confidence) (verified as of 2026-10-30) — [source](https://www.mongodb.com/docs/atlas/billing/) ## Facts and statements - Atlas charges each paying or linked organization daily subscription uplift based on its own usage. At the paying organization’s billing-period end, Atlas distributes any unmet monthly minimum proportionally to usage. The paying organization still pays all charges. (low confidence) (verified as of 2026-10-30) — [source](https://www.mongodb.com/docs/atlas/billing/) - Linked organizations receive monthly invoices containing their own charges and a proportional subscription-cost share; the paying organization pays all charges. (low confidence) (verified as of 2026-10-30) — [source](https://www.mongodb.com/docs/atlas/billing/) - Proportional shared-cost allocation uses relative cost, consumption, or another agreed metric to divide a common pool. FinOps Foundation distinguishes fixed and variable proportions; Finout documents telemetry-based and customized-percentage alternatives. These sources describe allocation methods, not Atlas contract enforcement. (high confidence) — [source](https://www.finops.org/wg/identifying-shared-costs/) - Vantage's July 29, 2024 launch described allocating shared costs through virtual tags using another cost dataset or labeled business metric as the proportional driver. This establishes a tooling pattern, not automatic reproduction of Atlas minimum charges. (low confidence) (verified as of 2024-07-29) — [source](https://www.vantage.sh/blog/vantage-launches-dynamic-cost-allocation) - FinOps Foundation's spend-proportional support example excludes the support pool itself from the weighting denominator; Vantage likewise separates the input weighting dataset from the output cost pool. For an internal minimum-shortfall model, keep those inputs explicit to avoid circular allocation. The last sentence is a methodological inference. (medium confidence) — [source](https://www.finops.org/wg/identifying-shared-costs/) - Atlas allocates cross-organization subscription costs in proportion to usage. Its 6 October 2021 changelog records the introduction of proportional subscription-charge allocation across linked organizations; current billing documentation describes this allocation on linked-organization invoices. (medium confidence) (verified as of 2026-10-30) — [source](https://www.mongodb.com/docs/atlas/billing/) - The Atlas documentation illustrates a $799 minimum with $400 and $200 of subscription uplift across two linked organizations and no charges in the paying organization. It allocates the remaining $199 as $132.70 and $66.30 respectively; these are the documented example amounts, not a published rounding specification. (low confidence) (verified as of 2026-10-30) — [source](https://www.mongodb.com/docs/atlas/billing/) - An analytical proportional-allocation model is A_i = R × u_i / sum(u), where R is the already-determined shortfall and u_i is an organization’s eligible allocation basis for the same period. This is a mathematical interpretation of Atlas’s proportional rule and FinOps proportional-allocation guidance, not a documented Atlas API formula; it requires a positive denominator. (medium confidence) — [source](https://www.mongodb.com/docs/atlas/billing/) - FinOps guidance distinguishes infrequently updated fixed allocation percentages from variable percentages based on current costs, usage, or another metric. Vantage’s allocation design illustrates the latter: it derives proportions from another cost dataset or business metric and applies them to a selected shared cost pool. (high confidence) — [source](https://www.finops.org/wg/identifying-shared-costs/) - Vantage’s 29 July 2024 launch article describes configurable input-cost filters, output-cost filters, and virtual-tag targets for dynamic allocation. It also distinguishes daily allocation from unamortized costs allocated using the whole billing period. This is generic allocation tooling evidence, not proof of an automatic Atlas minimum-shortfall integration. (low confidence) (verified as of 2024-07-29) — [source](https://www.vantage.sh/blog/vantage-launches-dynamic-cost-allocation) - FinOps guidance does not prescribe proportional spend as universally fair: it offers even, fixed-proportional, and variable-proportional methods, warns that total-cost proportions can miss actual consumption patterns, and recommends agreement with budget owners. These internal accounting choices do not alter Atlas’s documented invoice allocation. (medium confidence) — [source](https://www.finops.org/wg/identifying-shared-costs/)