Aside from being (in my opinion) a bad business practice, it's also lying to the shareholders. You see, that $80 Billion figure would be smaller if they'd pay the manufacturers in a reasonable timeframe.
I didn't jump in because I particularly care how Apple pays vendors, but because many people on HN are considering freelancing and bootstrapping, and they should know: big companies are never going to pay them on time. Keep cash in the bank.
Your comment about Apple's balance sheet is pretty silly.
Apple has 90 days of non paid supplies on the books (and $80 billion in the bank - "cash and investments" as stated in the article).
If they'd (OK... IDEALLY) pay all of them at once and continue paying supplies as they get delivered, only then would their balance sheet look realistic.
Or, am I missing something?
By delaying payments Apple can use the cash for other short-term investment opportunities. In Apple's case, their accounts payable is probably in the billions. As an example: If Apple has a $10 billion accounts payable and instead of paying it right away they waited for 3 months and invested that $10 billion on short-term securities with a 10% return, Apple would earn $1 billion in that 3-month period vs. ZERO if they paid their liabilities right away.
Accounting:
1) Buy parts for $1000
debit Parts Inventory $1000 credit Liabilities - Accounts Payable $1000
2) Pay vendor
debit Liabilities - Accounts Payable $1000 credit Cash $1000
The single man startups I worked for would pay their invoices promptly, while multi-nationals seemed to consider "net 30" to mean they shouldn't even consider paying until 30 days after receipt, and seemed to have a policy that they wouldn't pay until hassled.
* We don't have a payments/procurements department, so "payment" usually means me, Dave, or our finance person just cutting a check.
* We derive no meaningful benefit from withholding payment (pennies of interest, versus hundreds of dollars of lost cycles).
At giant companies, carefully managing payables probably makes an enormous difference. When you say "operations excellence", stuff like how vendors are paid is one of the first things many people think of.
The payments department won't even look at the invoice if it's missing that.