According to Forbes they were
> For most of the 20th century, stock buybacks were deemed illegal because they were thought to be a form of stock market manipulation.
https://www.forbes.com/sites/aalsin/2017/02/28/shareholders-...
> For most of the 20th century, stock buybacks were deemed illegal because they were thought to be a form of stock market manipulation.
https://www.forbes.com/sites/aalsin/2017/02/28/shareholders-...
Henry Singleton who founded Teledyne is known as the buyback king because he used his high-flying stock in the 1960s to snap up tons of smaller electronics companies, and when his stock crashed to $8 during the years of stagflation, snapped up millions with buybacks. In the end, he had used his stock as a currency to acquire dozens of companies at what essentially became 80% discounts.
http://csinvesting.org/wp-content/uploads/2015/05/Dr.-Single...
A very good very in-depth PDF read about him if you're interested in this type of thing.