Inventory is the set of goods a company holds to sell, transform, or consume in normal operations: raw materials, work in process, finished goods, and merchandise · and, in corridor logistics, also stock in transit or in quarantine. On the books it is a current asset (NIF C-4 / IMCP practice); operationally it is what the distribution center (DC / CEDIS) can or cannot release to a trip.
If the screen says “we have stock” but the dock cannot tender, you do not have available inventory: you have a story. This guide locks the concept, the types that matter for Mexico–U.S. shippers, Mexican valuation, and how a stock error turns into expensive freight.
- physical · system · tenderable
- 3 layers
- the ones that move freight and OTD
- 8 types
- current asset · confirm with accountant
- NIF C-4
- OCL closes the trip · not the WMS
- Post-stock
Cluster: warehouse functions · cargo types · OTD · POD · CFDI traslado · distribution costs.
What inventory is (usable answer)
Inventory answers: what stock do we have, where is it, and in what state? It is not only “what is in the spreadsheet.” It includes received, put away, reserved, in transit, and blocked. Without that clarity, picking, shipping, and freight run on false data. Node detail: eight warehouse functions.
Under Mexican financial reporting standards (NIF C-4, issued by CINIF and applied through IMCP practice), inventory is presented as a current asset and measured at cost or net realizable value, whichever is lower. Confirm policies with your accountant · this is an operating playbook, not a legal opinion.
Physical vs system vs available to tender
Three readings of the same SKU. Mixing them is the expensive way to “win” fill rate on screen and lose the appointment in the yard.
Physical
What it measures: Units in rack, dock, or trailer
Operating question: Is it really here?
Typical failure: Late counts · untyped shrink
System (WMS/ERP)
What it measures: Recorded balance
Operating question: Does the system match the floor?
Typical failure: Unscanned moves · ghost adjustments
Available to tender
What it measures: Releasable to a trip now
Operating question: Can I assign carrier and appointment?
Typical failure: “Green” stock in quarantine or without docs
Ecommerce talks about “physical vs accounting.” On the corridor you need the third layer: available to tender. Without it, traffic sells capacity the dock cannot load.
Eight types that matter in DC and corridor
Mecalux and Creditea list dozens of classifications (fiscal period, consignment, seasonal…). Useful inside a WMS. For Mexico–U.S. shippers, these eight change space, capital, and freight.
Raw materials (RM)
Short definition: Inputs to manufacture
Corridor example: Steel / resin in a Nuevo León plant DC
Warning signal: RM stockout to line stop · expedite freight
Work in process (WIP)
Short definition: Partially finished between stations
Corridor example: Partial chassis in assembly
Warning signal: Inflated WIP hides process bottlenecks
Finished goods (FG)
Short definition: Ready to sell or ship
Corridor example: FG pallets in blue/orange racking
Warning signal: FG “available” without lot/quality release
Merchandise
Short definition: Bought for resale (no transformation)
Corridor example: Multi-brand distributor in Guadalajara
Warning signal: ABC mix without turns · dead capital
In transit
Short definition: Between nodes · not yet received
Corridor example: Monterrey–Laredo in a dry van
Warning signal: Marked available at origin or destination
Safety stock
Short definition: Buffer vs demand / lead-time uncertainty
Corridor example: A-SKU buffer ahead of border crossing
Warning signal: Eternal “safety” = obsolete in disguise
Obsolete
Short definition: No useful movement (e.g. 12+ months)
Corridor example: Discontinued model in aisle C
Warning signal: Burns slots · distorts turns
Quarantine / hold
Short definition: Not releasable (quality, fiscal, hold)
Corridor example: Lot on hold pending inspection
Warning signal: Shows as free stock on screen
Mexico–U.S. examples
Three scenes for the same SKU. Same label · three different truths about service.
Monterrey DC
What the system says: 120 FG pallets available
What the yard shows: 118 in rack · 2 in quarantine without typed hold
Impact: Tender for 120 · dock cuts at 118
En route to Laredo
What the system says: Origin already “shipped” · destination not received
What the yard shows: Unit in transit with POD pending
Impact: If you sell it again · double promise
Transfer between own sites
What the system says: Internal adjustment without aligned CFDI traslado
What the yard shows: Goods moved · weak fiscal file
Impact: SAT / audit dispute · see traslado guide
Document moves between your own sites under current fiscal criteria: CFDI traslado guide. Do not invent the fact pattern · confirm with your tax advisor.
Valuation in Mexico: FIFO, average, LIFO
Valuation assigns cost to what you sell and what remains. In Mexico, the accounting frame (NIF C-4) and the tax frame (LISR) do not always match word for word: document the method and do not change it lightly.
FIFO (PEPS)
Idea: Oldest receipts leave first
Typical MX use: Widely used · aligns with physical rotation
Note: Ending inventory ≈ recent costs
Weighted average
Idea: Average cost of balances
Typical MX use: Simple · acceptable in many industries
Note: Smooths price spikes
LIFO (UEPS)
Idea: Newest receipts leave first
Typical MX use: Not the NIF C-4 standard
Note: Do not use it “because the ERP offers it”
When inventory lies to freight
A stock error does not stay in the aisle. It becomes a missed appointment, broken on-time delivery (OTD), empty miles, and misbuilt vouchers.
System > physical
What operations sees: Picking short-ships the order
What freight sees: Appointment / OTD fail · redelivery
Signal: Screen fill rate ≠ floor
Available while quarantined
What operations sees: Untyped hold
What freight sees: Unit arrives · dock rejects
Signal: Accessorials / detention
In transit counted twice
What operations sees: Double stock promise
What freight sees: Second empty or partial trip
Signal: Empty miles · distribution cost
Inter-site transfer poorly documented
What operations sees: Excel “balances”
What freight sees: CFDI traslado / Carta Porte misaligned
Signal: Fiscal risk + accounts payable freight dispute
The cost of that lie shows up in distribution costs · not only in “warehouse shrink.”
Minimum operating cycle
A short cycle keeps the dashboard attached to the floor. Go deeper on counts in cycle counting and continuous recording in perpetual inventory.
Stock cycle
From receipt to adjust
Elige un paso para ver el detalle
Detalle del paso · 01
Receive and type
Step 1
Control checklist
Run it Monday with traffic and the warehouse. If you fail three or more, the problem is not “missing WMS”: it is state governance.
Elige un paso para ver el detalle
Detalle del paso · 01
Separate available-to-tender from total on-hand
From stock to the trip file
OCL Cargo is an autonomous transportation management system (TMS) with computer-use agents: it does not compete with your WMS for rack balances. It closes the trip file after stock leaves · appointment, POD evidence, tower exceptions, and an auditable trail for accounts payable.
Who owns exceptions? Your team. Agents prepare the file; they do not invent commercial criteria. When in scope, OCL can stamp invoice and Carta Porte. Typical pilot 6–8 weeks; recovery pattern 5–7% when auditing 100% of the pilot flow · pricing signal from ~$50 MXN per shipment depending on scope.
Key takeaways5 points
- Inventory = goods to sell, transform, or consume · plus in-transit and blocked stock ecommerce pages often skip.
- Three layers: physical · system · available to tender. If you only trust the WMS, you invent service.
- Types that move freight: RM, WIP, FG, merchandise, in transit, safety, obsolete, quarantine.
- Stock error to missed appointment, broken OTD, empty miles, accessorials, and bad CFDI traslado between own sites.
- OCL does not replace the WMS: it closes the trip file after stock leaves. Who owns exceptions? Your team.
Is your “available” inventory not tenderable?
Related reading
Frequently asked questions
The goods a company holds to sell, transform, or consume in normal operations: raw materials, work in process, finished goods, merchandise · and, in corridor logistics, stock in transit or quarantine. On the books it is a current asset (Mexican NIF C-4 / IMCP practice); operationally it is what the distribution center (DC / CEDIS) can or cannot release to a trip.
Physical is what sits in racks, dock, or trailer. System is what the WMS/ERP shows. When they diverge, you have a discrepancy. Worse: stock marked “available” that is not ready to tender (quarantine, hold, missing documents). See the physical / system / available-to-tender matrix in this guide.
For shippers and DCs on the Mexico–U.S. corridor: raw materials (RM), work in process (WIP), finished goods (FG), resale merchandise, in transit, safety stock, obsolete, and quarantine/hold. Ecommerce or WMS taxonomies can be longer; these eight move freight, on-time delivery (OTD), and CFDI traslado (transfer invoice) risk.
Under NIF C-4, common cost-assignment formulas include FIFO (PEPS) and weighted average; LIFO is not the Mexican accounting standard. For tax effects, confirm the method with your tax advisor (LISR art. 41 and documented policies). This guide is an operating playbook, not a legal opinion.
Lying stock creates missed appointments, redeliveries, empty miles, detention accessorials, and misbuilt CFDI traslado between your own sites. The warehouse “has” the SKU · the truck arrives · the dock cannot release. See distribution costs.
No. The WMS owns on-hand balances in the node. OCL closes the trip file after stock leaves: evidence, exceptions, pre-pay for accounts payable, and, when in scope, stamping invoice and Carta Porte. Who owns exceptions? Your team.