1) In your MProfit portfolio summary screen, right click on the Stock name and select Other Transactions. Then, click Add Demerger.   

2) Enter the effective date of demerger.

Next, proceed to populating the Demerger Details table.

For the parent company, enter the balance quantity of new shares and corresponding amount retained after the demerger, as per the demerger ratio.

For each new company, click into a new row and press Ctrl + Shift + S to add the name of the new company. Then add the quantity of new shares received and corresponding amount, as per the demerger ratio.

Example below: