The acceptance ratio is the percentage of shares that the company will buy back from each shareholder. Since buybacks have a fixed size (in terms of number of shares or total amount), the company may not be able to accept all the shares tendered.  

For example, if the acceptance ratio is 30% and you tender 100 shares, only 30 shares will be bought back. The remaining 70 shares will be returned to your demat account after the offer closes.  

The acceptance ratio is typically higher for shareholders in the retail category (those holding shares below a certain value), as SEBI regulations reserve a minimum 15% of the buyback for retail investors.