* If you are in the US, go to one of the credit bureau sites (Transunion/Experian/Equifax) and sign up for a fraud alert. You'll need to provide your current phone number and what this does is this: no fintech/bank is supposed to create an account or issue credit in your name unless they have verified the activity with this phone number.
* If you have previously been a victim of fraud, sign up on one of the aforementioned bureaus for an Extended Fraud Alert.
* Isolate your email tied to your finance accounts from regular email that you give out on website signups, doctors' offices, etc. Only your bank/brokerage needs to know that this email exists
* If you can afford to, pay to track leakage of this information on the dark web or password sharing forums
* Use a password manager
* Use 2FA on all your accounts and use an authenticator app if possible. It's not ideal but it's better than the SMS/email 2FA
* If your telecom provider supports it, ask them about how you can protect yourself from sim-swapping and porting. Add a PIN to your phone provider account if you can.