Apple has issued debt to buyback shares [0]. One problem many large tech companies have is that their cash is stranded overseas due, in part, to…creative…tax/accounting arrangements [1]. They lobbied [2] for years for a tax break to repatriate this cash, and eventually got a tax break on repatriation for “foreign” profits close to what they had asked for [3]. Before that law was passed, it was common to borrow to fund share buybacks due to not wanting to pay the repatriation tax. As far as I can tell, it is still common due to the low interest rate environment of the last several years.

0 - https://www.nasdaq.com/articles/apple-shores-up-%2414b-in-de...

1 - https://www.news.com.au/technology/online/security/double-ir...

2 - https://money.cnn.com/2011/02/16/news/companies/repatriation...

3 - https://marketrealist.com/2018/02/cisco-bringing-67-billion-...