Business expenses are deductible. For example, if you are a reseller, you can spend before the end of the year to increase your inventory (and decrease your profits for that year).
What you describe only works for cash basis taxpayers. Public companies are all accrual basis taxpayers. Under accrual accounting increasing your inventory affects the financial statements as follows:
* Balance sheet: decreases cash/cash equivalents entry and increases the inventory balance sheet entry (in equal amounts), resulting in no change to net assets or equity
* Income statement: no effect
* Cash flow statement: will show up as a change to inventory, reducing operating cash flow and total cash flow
Only operating expenses, but in any case you will pay more next year.