Why it is carried out
A TOB is typically used to acquire control, turn a company into a subsidiary, or take it private (delisting following a full subsidiarization). The bidder publicly announces in advance the maximum and minimum number of shares it wants to acquire, the tender price, and the offer period, and invites shareholders to tender their shares under those terms.
What to keep in mind
The tender price is often set at a certain premium above the market price, which is one reason it can be seen as positive for the share price. That said, the offer may fail if the number of shares tendered falls short of the minimum threshold, and questions about the fairness of the price can also arise, so outcomes vary case by case.