Could someone give a simplified explanation of the economics of how the recent renounceable rights issue and issuance of MCB affect the value of SIA shares and its value as a long term investment?

Basically, this rights dilute your shares. if you subscribe it, you retain the supposed value. but if you don't your shares are worth less now. the dilution is 60%. fair value of SIA is now ~$4.40. so if you dont subscribe, your paper loss would be your average price - $4.40.