I wonder how much of this is related to the harsh corporate tax environment in the US. Take Apple for example. They can't use their offshore cash to directly

I wonder how much of this is related to the harsh corporate tax environment in the US. Take Apple for example. They can't use their offshore cash to directly fund buybacks or dividends without repatriating the money and paying high US corporate taxes on it. Instead, they have borrowed against their offshore cash to make buybacks, and then whatever cash is needed for debt service can either be funded from operating income or by importing offshore cash in a relative trickle, with a correspondingly low tax burden, while the money grows virtually tax-free overseas. So by doing share repurchases with borrowed money, shareholders and executives can reap the benefits of offshore cash without subjecting it to the enormous tax burden they would by directly repatriating the money. As long as corporate profits are still piling up abroad, this trend of corporate buybacks will likely continue.