Amazon
FBA and FBM, without the stockout tax
A stockout costs more than the sales it misses: it costs rank, the Buy Box, and the advertising spend that fed both. We forecast to demand and replenish before that happens.
We plan replenishment on weighted velocity across FBA stock, 3PL stock and units in transit, so a reorder quantity is a number with reasoning behind it rather than a guess made in a spreadsheet. Every week carries a days-of-cover position and a plain call on what to ship.
The same model watches the other end: aged inventory, long-term storage exposure, inbound non-compliance and removal orders. Overstock is quieter than a stockout and often more expensive.