A linked bank account is an electronic connection between two financial accounts that lets you see balances in one place and move money between them. The link can join two accounts at the same bank, two accounts at different banks, or a bank account and an outside platform like a brokerage or payment app. Setting one up is usually quick, but the connection carries transfer rules, security exposure, and legal consequences worth knowing before you click through the setup screens.
The Three Kinds of Links
Account connections fall into three groups based on where the accounts sit.
Internal links join two accounts at the same bank, such as checking to savings. They power features like automatic savings sweeps and overdraft protection, and transfers between them are usually instant because the money never leaves the institution.
External links connect accounts at two different banks. Money moves through the Automated Clearing House (ACH) network, so transfers take longer than internal ones.
Third-party links connect a bank account to an outside platform: a brokerage, a robo-advisor, a peer-to-peer app. These use secure programming interfaces so you can fund investments or send payments from a digital wallet.
What You Need to Set One Up
Two numbers do most of the work. The first is your routing transit number, a nine-digit code that identifies your bank.1TFX: Treasury Financial Experience. Routing Transit Number (RTN) The second is your individual account number. Both appear on the bottom of a physical check and in the account details area of your bank’s website or app.
Some institutions also ask for the legal name of the receiving bank to confirm the routing number matches. If you link through a digital platform, you may need your online banking login so the two systems can talk. Depending on the bank, you may also sign an ACH authorization confirming you have the right to move money from the account.2Consumer Financial Protection Bureau. ACH Authorization for Electronic Account Access
How the Link Gets Verified
Before the connection goes live, the platform confirms that you actually control the account you’re linking. Two methods dominate.
Micro-Deposit Verification
The institution sends two small credits, usually under a dollar, to the account you want to link. They arrive in one to three business days. You then log back in and enter the exact amounts. Report them correctly and the link activates. Miss the platform’s deadline and the pending link is canceled.
Instant Verification
Many platforms now offer instant verification and skip the waiting period. The safer version uses OAuth: you log in through your bank, and the platform receives a token granting limited access without ever seeing your username or password. When OAuth isn’t available, the platform may ask for your banking credentials directly, which carries more risk.
Transfer Speed and Access to Funds
Transfers between linked accounts at different banks travel through the ACH network, a nationwide system banks use to exchange batched electronic credits and debits.3Federal Reserve Board. Automated Clearinghouse Services Standard ACH transfers usually settle in one to three business days. Same-day ACH is also available, though your bank may add a fee for it.4Nacha. Same Day ACH
Once funds arrive by electronic payment, federal rules require your bank to make them available for withdrawal no later than the next business day.5eCFR. 12 CFR 229.10 – Next-Day Availability Electronic deposits are not subject to extended exception holds, so the bank cannot delay access past that window. Internal transfers between accounts at the same bank typically post the same business day.
Limits and Fees
The old federal cap of six outgoing savings transfers per month under Regulation D ended in April 2020, and savings accounts can now handle unlimited transfers.6Federal Register. Regulation D: Reserve Requirements of Depository Institutions Individual banks may still set their own transaction limits or charge fees, so read your account agreement.
Most banks handle standard outgoing ACH transfers at no charge. Expedited or same-day transfers, or transfers you initiate by phone or in person, may carry fees. Banks also commonly set daily or monthly dollar caps on outgoing transfers; these are not federally set, so they vary. If you plan to move a large sum, check the cap first.
Security Risks and Your Liability
Linking accounts, especially to third-party platforms, exposes your financial data in ways worth thinking through.
Credential Sharing
Platforms that use screen scraping instead of OAuth store your banking login. That creates a target for hackers and can lead to unauthorized transactions and identity theft. Some data aggregators operate under lighter regulatory oversight than banks themselves on privacy and security.7FINRA. Know Before You Share: Be Mindful of Data Aggregation Risks If you stop using a platform that has your credentials, cancel your account there and revoke access; an unused connection left open still points at your data.
What You Owe If Someone Steals From a Linked Account
Federal law (Regulation E) caps your liability for unauthorized electronic transfers, but how much you owe depends on how fast you report the problem:8eCFR. 12 CFR 1005.6 – Liability of Consumer for Unauthorized Transfers
- Report within two business days of learning about the unauthorized access, and your liability is capped at $50.
- Miss the two-day window but report within 60 days of receiving the statement, and your liability can reach $500.
- Wait longer than 60 days after the statement, and you can be liable for the full amount of any transfers that occur after that window closes.
Watch your linked accounts and report anything unfamiliar right away. Every day of delay raises your exposure.
What Linking Does and Doesn’t Change Legally
Linking two accounts does not merge them or transfer ownership. Each keeps its original owner, and a link alone gives no third party legal rights to your money. Two rules matter beyond that.
Right of Setoff
Most bank account agreements include a right-of-setoff clause. It lets the bank pull money from one of your accounts to cover a debt or negative balance in another account you hold at the same institution, often without notice. If your checking is overdrawn by $500, the bank can take that $500 from your linked savings. The bank can take up to the full amount owed, provided the funds are available. This right generally applies within the same bank, not across accounts you’ve linked at different institutions.
FDIC Insurance Doesn’t Grow When You Link
Linking multiple accounts at the same bank does not add coverage. All deposits you hold in the same ownership category at the same FDIC-insured bank are added together and insured up to $250,000 in total.9FDIC. Understanding Deposit Insurance A $150,000 checking balance and a $150,000 linked savings balance in your name alone at the same bank total $300,000, of which only $250,000 is insured. Accounts in different ownership categories, such as individual and joint, are insured separately.
Stopping Payments or Unlinking
You can stop a preauthorized electronic transfer at any time. Under Regulation E, notify your bank at least three business days before the scheduled payment. Notice can be oral or written. If the bank asks you to follow up in writing within 14 days, it must tell you so at the time of the oral request; an oral order that isn’t confirmed in writing expires after 14 days.10eCFR. 12 CFR 1005.10 – Preauthorized Transfers
To unlink fully, take two steps. First, revoke authorization with the company or platform that initiates the transfers. Second, tell your bank the authorization is no longer valid. Once notified, your bank must block future debits from that source.11Consumer Financial Protection Bureau. How to Stop Automatic Electronic Payments From Your Account Keep watching your statements for at least two billing cycles to catch anything that slips through.
A Note on Payment Apps and Tax Reporting
If you link a bank account to a platform like Venmo, PayPal, or Cash App and receive payments for goods or services, those transactions can trigger tax reporting. Under current law, third-party payment platforms must file a Form 1099-K for any user whose gross payments exceed $20,000 and whose total transactions exceed 200 in a calendar year.12Internal Revenue Service. IRS Issues FAQs on Form 1099-K Threshold Personal transfers, like splitting rent with a roommate, do not count. Payments for goods or services do.