How Do I Link Existing Shares to a Newly Opened CSCS Account in Nigeria?

Before doing anything, find out your existing CHN.
You can obtain your CHN from your existing broker or through the relevant CSCS account information available to you.
This is important because you want the new broker to know that:
“I am an existing investor. I already have a CHN.”
Don’t simply assume that because you have opened a new brokerage account, you need a brand-new CHN.
Confirm your new CSCS account details
Ask your new broker for the details of the CSCS account opened for you.
You may have:
Old broker
Existing CHN
Existing CSCS account number
New broker
Same CHN
New CSCS account number
That situation can be perfectly normal.
The important thing is to make sure your personal information is correctly

Tell the new broker you have existing holdings
Contact your new stockbroker.
Tell them clearly:
“I have existing shares with another stockbroker and I want to transfer them to my account with you.”

Complete the required transfer documentation
Your broker may require you to complete a securities transfer form or other documentation.
The exact requirements can vary depending on the broker and the type of transfer.
You may be asked for information such as:
Your name
CHN
Old CSCS account details
New CSCS account details
Stockbroker details
The shares you want transferred
Your signature
Identification documents, where required
Your broker should tell you exactly what is required.

Then, Wait for the transfer to be processed
After the required documents and instructions have been submitted, the transfer has to be processed.
It may not happen instantly.
So don’t assume that something is wrong simply because you don’t see the shares in your new broker’s app immediately.
Allow the relevant parties to process the transfer.
If it takes longer than the timeframe your broker gave you, contact them and ask for an update.