What is a Rights issue?
A rights offering is a right offered to existing shareholders to purchase additional shares, in proportion to their existing holdings. The Rights issue price will always be at a lesser price than the current market price of the stock. The reasons for the rights issue is generally to raise funds to Pay off debt, Purchase of assets to the business and acquiring another company etc.
You can learn more about Rights issue, refer to this chapter on Varsity.
Note: You can track the list of all corporate actions here.