Shares of Walgreens Boots Alliance have lost about half their value in the past year, as the chain has faced pressure in its retail and pharmacy businesses.

Walgreens Boots Alliance says it has agreed to be acquired by the private equity firm Sycamore Partners as the struggling retailer looks to turn itself around after years of losing money.

There are plenty of reasons to be skeptical that private equity will help Walgreens get out of turbulent times.