SIOP stands for sales, inventory, and operations planning. It is a recurring business process for agreeing on expected demand, the inventory to carry, and the supply needed to fulfill that demand within capacity and financial constraints. When sales wants more stock and finance wants less cash in inventory, the review puts both requests against the same supply evidence.
The output is an approved operating plan with stated assumptions and accountable decisions. In manufacturing, that means you can explain which demand the plan serves, which shortages remain, and what the inventory commitment costs. A review cannot settle those questions if the sales file, warehouse snapshot, and financial model describe different products or periods.
SIOP and S&OP share a planning purpose
S&OP means sales and operations planning. Both terms describe cross-functional planning that brings demand and supply into an agreed business plan; SIOP makes inventory explicit in the name. Inventory and finance can already be part of S&OP, so the acronym alone does not establish a more advanced process.
Compare the decisions your process supports. Does it set an inventory target alongside the service promise? Can finance challenge the cash required to support that target? Can operations show the constraint behind a supply shortfall? Renaming the meeting adds no decision rights or evidence; assigning owners and documenting the trade-offs does.
Demand planning contributes the expected demand and its assumptions. SIOP brings that demand into a broader review with inventory, supply, and finance. Keep the unconstrained demand view (what customers are expected to want) separate from the supply-constrained plan, so an inability to produce does not disappear into a lower forecast.
A SIOP process from shared inputs to approved decisions
Start with a monthly review and choose a horizon that reaches beyond the commitments you must make now. Long material lead times and production reservations need a longer view than products you can replenish before the next review. Use the following five stages as an operating design, with a named owner and an explicit output for each.
| Stage | Accountable owner | Required output | Failure to catch |
|---|---|---|---|
| Input preparation | Planning lead | Dated inputs with common products, units, and periods | Missing locations or mismatched pack sizes |
| Demand review | Commercial lead | Agreed demand assumptions and changes | Bookings added to a forecast that already includes them |
| Supply and inventory review | Operations lead | Feasible supply, stock targets, and unresolved gaps | Held stock counted as available or shared capacity counted twice |
| Financial reconciliation | Finance lead | Comparable service, margin, and cash implications | Inventory purchases treated as an immediate cost of sales |
| Executive approval | Executive sponsor | Selected plan, accepted risks, owners, and deadlines | A shortage discussed without a decision or accountable action |
Prepare inputs with a visible cutoff
Your planning lead should gather sales history, the current forecast, stock, open supply, and capacity assumptions against a declared cutoff. Salesforce opportunities and NetSuite orders represent different stages of a sale. Keep pipeline, booked orders, and shipments identifiable so a commercial opportunity is not counted again when it becomes an order.
Record when each source was received and which period it covers. A late warehouse export must remain a visible gap; carrying its old quantity forward without a warning turns an unknown position into an apparent commitment. Keep a corrected input distinguishable from the version used for the prior approval.
Review demand assumptions before supply constraints
Your commercial lead should identify why demand changed: a new contract, a product launch, a lost account, or a changed baseline. Keep the forecast version and the reason for each override. Define how booked orders consume the forecast so the same demand does not enter the plan twice.
Preserve the level at which the forecast was made. A family forecast needs an allocation rule before it becomes demand for individual stock keeping units (SKUs), and that rule remains an assumption. Retain the sales history and product mix used to make the allocation so operations can test the required materials and capacity.
Test supply and inventory against the demand plan
Your operations lead should show what can be supplied by period and where it falls short. Separate stock on hand from stock released for sale, and distinguish confirmed incoming supply from a requested delivery date. Apply demand to the correct product and location; a family-level surplus can coexist with a shortage of the pack a customer ordered.
Inventory targets belong in this review because the plan must explain where stock buffers a constraint and where it creates excess exposure. Manufacturing adds material, yield, and shared-line questions; SIOP in manufacturing: capacity, inventory, and cash follows those inputs through the review.
Reconcile operational choices with financial consequences
Your finance lead should translate each proposed option using the same quantities and periods as the supply plan. Include the inventory investment, expected margin, and timing of payments and collections. Purchasing materials consumes cash on a different schedule from recognizing the cost of a sale, so a profitable option can still require cash before customer receipts arrive.
Approve a plan and the risks it leaves open
Your executive sponsor should choose among the prepared options and record the accepted shortage, inventory exposure, or cost. Attach an owner and deadline to each follow-up. Store the selected plan alongside its assumptions so the next review can distinguish an execution miss from a change in demand or source evidence.
Shared definitions keep the cycle reproducible
When you add a plant, warehouse, or contract manufacturer, its data should follow the same rules as existing inputs. Maintain a product mapping with dated unit conversions, a planning calendar, and separate definitions for demand, available stock, and confirmed receipts. A spreadsheet total cannot tell you whether a newly added warehouse is missing or whether production quantities use the same unit as customer orders.
Keep actuals, forecasts, and approved plans distinct. Compare forecast error at the level where the forecast was made, measure service against a declared order or unit basis, and date inventory positions. Those definitions let you explain a movement in the review without changing the measurement midway through it.
How Permute prepares evidence for a SIOP review
Permute is the context layer we sell between business data and the AI tools you use. We connect sources such as SAP, NetSuite, and Excel, then reconcile product identities and conflicting records under declared rules. A connected spreadsheet can supply a contract manufacturer's export without implying a native integration with that manufacturer.
We encode agreed definitions once so recurring dashboards and data outputs use the same product, period, and stock rules. Source evidence and freshness remain part of the result, and how the data is handled determines which users and agents can access it.
An operations lead can ask which products have a supply gap against an imported demand plan and inspect the source rows behind the answer. We supply governed inputs to Claude, ChatGPT, and Copilot as well as to dashboards, so the explanation can be checked against the data and rules used.
Test one planning input
Bring a sales source and an inventory file into a workspace, then inspect how product mappings and stock definitions affect the result.
Forecasts, supply choices, and approval stay with their owners
We are not a forecasting engine. We prepare governed history and inputs for the forecast you create in your planning tools. We read the connected planning sources; this workflow does not release production orders, change ERP inventory, or place purchases. Capacity optimization, the service promise, and approval of the operating plan remain with your planning systems and accountable people.
An approved plan must explain its commitments
SIOP brings expected demand, inventory, and supply into an operating plan that finance and leadership can evaluate. The cycle works when each stage carries shared inputs forward and exposes the choices those inputs cannot settle. Approving the plan means accepting a stated service, stock, and cash position with owners for unresolved actions. At the next review, compare execution against that recorded commitment before changing it.
Review the evidence behind your planning cycle
Bring your current review pack. We will examine source gaps, conflicting definitions, and the data needed to support the decisions you make.
Questions about starting a SIOP cycle
Can a small team run SIOP without separate departments?
Yes. One person can own several inputs, but give each review responsibility a name and keep executive approval explicit. A small team can use a shorter review pack as long as it records the demand assumption, supply gap, financial consequence, and decision.
What happens when a supplier slips between monthly reviews?
Use a short-term exception review to decide what must change before the next planning cycle. Record the departure from the approved plan and escalate decisions that exceed the delegated service or spending limits. Bring the changed assumption into the next SIOP review.
Can the first cycle run in Excel or Google Sheets?
Yes, provided you control input versions, units, definitions, and the approved output. Keep the working model separate from the approved plan so later edits do not erase the decision record. When source collection and reconciliation outgrow that control, automate those inputs before adding more spreadsheet logic.