As much as even

[bingojohn]

An inventory equal to 90 days sales is as much as even the strongest businesses carry, and then only as a way to anticipate higher prices or ensure against shortages.

What on earth does this sentence mean??

[devesh]

Even the strongest businesses carry 90 days inventory.
why?
1. to ensure against shortages
2. anticipate higher prices(they will realise more value for same cost of goods if price increases)