Your registered mobile number in your Demat account is not a minor administrative detail. It is the primary channel for trade confirmations, transaction alerts, OTP authentication for every sensitive account modification, and dividend and corporate action notifications. An outdated mobile number — one belonging to a handset you no longer use, a number you’ve relinquished, or a number linked to a different SIM — creates a cascading authentication problem that blocks you from virtually every sensitive function in your Demat account until it is resolved.
The good news is that updating it is a clearly defined, executable process. The challenge is that the process requires identity authentication from a channel other than the phone number being replaced — which is where most people hit friction. This guide removes that friction entirely.
Why Mobile Number Updates Are More Strictly Controlled Than Other Profile Changes
Changing a mobile number in a Demat account is deliberately treated as a high-security modification. Unlike updating an address or adding a nominee — which can be done through standard OTP verification to the existing number — replacing the registered mobile number itself cannot rely on OTP to the old number, because in many cases the old number is no longer accessible to the account holder.
Brokers and Depository Participants apply enhanced verification to mobile number updates specifically because the mobile number is the primary authentication channel for all other account modifications. Unauthorised access to your registered mobile number would give a bad actor the ability to initiate other sensitive changes through OTP. The update process is therefore designed to verify your identity through alternative, stronger channels.
The Online Process for Active Old Number Holders
If you still have access to your old mobile number — the SIM is active and receives OTPs — the online update process is the fastest route.
Log into your broker’s platform using your UAN or login credentials. Navigate to Profile or Account Settings and locate the Mobile Number section. Select the option to change or update the registered mobile number. The platform sends an OTP to your existing registered number for authentication. Enter this OTP to confirm that you are the account holder initiating the change. Then enter your new mobile number. A second OTP is sent to the new number to verify it belongs to you. Enter this OTP to complete the update.
This dual-OTP process — verifying both the outgoing and incoming numbers — is the most streamlined update path and completes the change within minutes on most modern broker platforms.
When You No Longer Have Access to the Old Number
This is the more complex scenario — you’ve changed your SIM, your old number was reassigned by the telecom operator, or your handset is lost. In this case the online OTP route is unavailable and an alternative verification path is required.
The process varies by broker but typically involves one of two approaches.
The first is a biometric or video-based identity verification. Several brokers now offer a mobile number update through a fresh Aadhaar-based OTP — using your Aadhaar-linked new mobile number for authentication. If your Aadhaar is already linked to your new mobile number, you can authenticate the Demat mobile update through this Aadhaar OTP channel without requiring access to the old number.
The second approach is an in-person or document-based process — visiting the broker’s nearest branch with original identity proof, submitting a mobile number change request form with signature matching the account records, and completing KYC re-verification. Processing through this route typically takes three to seven working days.
For brokers with robust digital infrastructure — Zerodha, Groww, Upstox — the Aadhaar OTP-based update is usually available through the account settings panel and is the preferred self-service route when the old number is inaccessible.
Step-by-Step for Aadhaar-Based Update
Log into your broker’s platform. Navigate to Profile and then Mobile Number Update. When prompted for OTP authentication to the old number, look for an alternative verification option — typically labelled as Verify via Aadhaar or Update without old number access. Select this option. Enter your Aadhaar number. An OTP is sent to the mobile number currently linked to your Aadhaar — which should be your new number. Enter this OTP to confirm identity. Enter your new mobile number for registration. Submit and await confirmation.
The key prerequisite is that your new mobile number must already be linked to your Aadhaar before attempting this route. If it isn’t, update your Aadhaar mobile linkage at an Aadhaar Seva Kendra first — this takes one visit and updates within 24 to 72 hours.
CDSL Demat and NSDL Demat: Depository-Level Update
For holdings in Demat form, the mobile number update at the broker level also needs to reflect at the depository level — CDSL or NSDL. Most broker-initiated updates automatically synchronise with the relevant depository. Verify this by checking your depository-level profile through CDSL’s Easi portal or NSDL’s SPEED-e facility after the broker update is confirmed — ensure the mobile number matches across all layers.
The Bottom Line
All three articles in this set address the practical operational dimension of financial products that sophisticated investors often overlook in favour of market analysis and return optimisation. A Step-Up SIP calculator converts annual salary increments into a precise, actionable projection of how much more wealth those increments could generate if systematically directed into investments. Loan sanction letter verification converts a moment of vulnerability — the hopeful receipt of an apparent approval — into a disciplined authentication process that separates genuine lending relationships from sophisticated fraud. And mobile number updating in a Demat account converts what feels like a minor administrative task into a security and authentication imperative that protects every subsequent sensitive action on the account. In financial management as in most things, the details that feel least urgent are often the ones with the largest consequences when they are neglected.
Frequently Asked Questions (FAQs)
Q1. How long does the mobile number update take to become effective across all platforms and systems?
A: For online OTP-based updates, the change is typically effective immediately for broker platform purposes. Synchronisation with the depository and with linked mutual fund registrars — CAMS, KFintech — may take one to three business days. During this window, OTPs for sensitive functions should be tested on the new number to confirm it is the active authentication channel before initiating any high-value transactions.
Q2. Do I need to update my mobile number separately in every financial account — broker, mutual fund platforms, bank — or does one update cascade across all?
A: Each platform and financial institution maintains its own registered mobile number independently. Updating your mobile number in your Demat account through your broker does not automatically update it in your mutual fund folios, your bank’s KYC records, or your income tax portal login. Each requires a separate update through the respective platform’s own process. Create a systematic checklist — broker, AMCs, bank, income tax portal, EPFO if applicable — and update each one in sequence within the same week.
Q3. Will an outdated mobile number in my Demat account affect my ability to file ITR or access my Annual Information Statement?
A: Directly, no — your ITR filing and AIS access are linked to your income tax portal credentials and your PAN, not to your Demat account’s registered mobile. Indirectly, if your Demat account is one of the sources of financial transaction data in your AIS — which it is — an outdated contact in your Demat account doesn’t affect data reporting but does affect your ability to access and act on Demat account information during tax season.
Q4. My Aadhaar is linked to an old mobile number I also no longer have access to. What’s the fastest way to resolve this before updating my Demat number?
A: Visit any Aadhaar Seva Kendra — you can locate one at uidai.gov.in — with your original Aadhaar card and any other identity proof. Request a mobile number update on your Aadhaar. Biometric authentication at the centre means no OTP to the old number is required — the update is processed through your fingerprint or iris scan. The new mobile number is linked to Aadhaar within 24 to 72 hours. Once confirmed, proceed with the Aadhaar OTP-based Demat mobile number update.
Q5. Is there any risk during the period when my old mobile number has been relinquished but not yet updated in my Demat account?
A: Yes — there is a genuine security risk. Relinquished mobile numbers in India are reassigned by telecom operators after a waiting period, typically sixty to ninety days. If your old number has been reassigned to a new user, that person could potentially receive OTPs intended for your Demat account authentication. The moment you relinquish or change your SIM number, updating your registered mobile in all financial accounts — Demat, bank, mutual fund platforms, income tax portal — should be treated as an immediate priority, not a deferred administrative task.
