When to move inventory to a US fulfillment center
Three numbers decide whether a brand should stop shipping order by order from Mexico and hold inventory in the US: volume, cost per order and returns.
By It’s the question I get most from brands already selling into the US: when should I stop shipping order by order from Mexico and hold inventory in a US fulfillment center?
There’s no magic number that fits everyone. There is a way to calculate it, and it fits in three questions.
1. Is your volume sustained, or a spike?
A great Black Friday doesn’t justify a warehouse. Consistent volume into the same country for several weeks in a row does.
Look at your US orders week by week over the last three months. If the line is steady (or growing), you have the base to absorb a fulfillment center. If you see one good month and three weak ones, not yet.
2. What is your real cost per order?
Most brands compare the shipping rate to the warehouse fee. The right comparison is all-in cost per order under both models:
| Order by order from Mexico | Inventory in a US fulfillment center |
|---|---|
| International parcel per order | Consolidated replenishment freight (per unit) |
| Duties, taxes and clearance per parcel | Consolidated import of the inventory |
| Border transit-time variability | Storage and pick & pack |
| Customer support for delays and surprise fees | Short domestic delivery |
| Returns that cross the border twice | Returns that never leave the US |
Past a certain volume, the right column wins. It also arrives faster, which lifts conversion: US shoppers don’t care where you operate from, they care how many days the order takes.
3. What do returns cost you?
The cost almost nobody calculates. A product returned from the US to Mexico crosses the border twice, each time with its own cost and paperwork.
If your category has high return rates (apparel, footwear, accessories), this alone can pull the decision forward by months.
The rule I use
The moment is when the all-in cost per order from a local fulfillment center is lower than shipping order by order, with sustained volume behind it.
- Before that point, you pay for capacity you don’t use.
- After that point, you lose margin and customers every week you wait.
Moving late isn’t the mistake. Not having the number in front of you is.
Before you ship the first container
- Classify your product correctly. Tariff classification and country of origin set what you pay to import the inventory.
- Decide who your importer of record (IOR) will be. Without one, the inventory doesn’t get in.
- Start with your fastest-moving SKUs. The rest can keep shipping direct.
- Ask the fulfillment center for its full rate card: receiving, storage per location, pick & pack, returns and monthly minimums.
With those four settled, the decision stops being a bet and becomes a calculation.
Key takeaways
- Measure sustained volume over several weeks, not your best month.
- Compare all-in cost per order: international parcel + customs + variability versus storage + domestic delivery.
- Returns from the US to Mexico cross the border twice; with US inventory they never leave the country.
- Moving late isn’t the mistake. Not having the number in front of you is.
FAQ
Do I need a US company to use a fulfillment center there?
Not always. Many fulfillment centers work with foreign brands, but importing the inventory requires an importer of record (IOR) and correct tariff classification. Check both with your customs broker and provider before shipping.
Can I start with part of my catalog?
Yes, and it’s usually the smartest move: bring only your fastest-moving SKUs to the US and keep the rest shipping direct from Mexico.
This article is for information only and reflects my personal view; it is not legal, tax or customs advice.
VP of Global 99 at 99minutos. 13+ years in international trade, freight and cross-border across Asia, Latin America and the United States.