Quick answer
Synthetic identity fraud is the use of a combination of personal information to fabricate a person or entity for dishonest gain[2]. Typically a real Social Security number is paired with a made-up name or birth date; the fake identity builds credit, then 'busts out' by borrowing heavily and disappearing[1].
Key points
- A synthetic identity mixes real information, such as a genuine Social Security number, with invented details.
- Fraudsters often behave like model customers for years, then max out every credit line and vanish: the 'bust-out'.
- Losses can look like ordinary bad debt, because there is no single victim who complains.
- The Federal Reserve's toolkit lists red flags such as a credit history that does not fit the applicant's age and contact details shared across many accounts.
- In the US, banks can check whether a name, date of birth and Social Security number match official records through the SSA's consent-based eCBSV service.
On this page
#How is a synthetic identity different from a stolen one?
In classic identity theft, a criminal pretends to be a real person, and that person eventually notices strange accounts or bills. A synthetic identity is different: it is a new 'person' assembled from parts. The Federal Reserve explained in 2019 that a synthetic identity is created by combining real information, such as a legitimate Social Security number (SSN, the US national identification number), with fictional information such as a made-up name, address or date of birth[1].
The Federal Reserve's payments improvement team, working with industry, uses this definition: the use of a combination of personally identifiable information to fabricate a person or entity in order to commit a dishonest act for personal or financial gain[2]. Most public material on the topic is from the United States, where the SSN plays a central role in opening accounts, so this page uses US examples.
| Question | Traditional identity theft | Synthetic identity fraud |
|---|---|---|
| Whose identity? | A real, existing person | An invented person built partly from real data |
| Who notices first? | Often the victim, through unexpected bills | Often nobody, until the debt goes unpaid |
| What does the loss look like? | A fraud claim by the victim | What appears to be a real customer who could not pay[2] |
#How do fraudsters build and use a synthetic identity?
The scheme is slow and patient. According to the Federal Reserve, fraudsters build up the creditworthiness of the synthetic identity over time, then 'bust out' by buying high-value goods and services on credit and disappearing[1]. The Fed's toolkit notes that synthetic credit profiles often consist mainly of authorised user tradelines, meaning the fake person is added as an extra user on someone else's established credit account, with little or no debt in their own name[2].
The typical life of a synthetic identity
Assemble
Combine a real identification number with an invented name, birth date and address.
Open accounts
Apply for credit in the new name so that lenders start recording a history.
Build history
Piggyback on established accounts as an authorised user and pay small bills on time.
Grow limits
Use the good record to win higher credit limits and more accounts.
Bust out
Max out every line, stop paying and disappear, leaving lenders with losses.
The Fed's toolkit gives an example in which an account approved with a $20,000 credit line was increased to $40,000 over three years of consistent on-time payments, then maxed out and charged off[2]. A charge-off is when a lender gives up on collecting a debt and records it as a loss. To understand why on-time payments raise limits, read how credit scores work.
Worked example
Worked example: the arithmetic of a bust-out
Using the Federal Reserve toolkit's example of a single account and assuming the fraudster maxes it out before vanishing. Figures were computed with code.
- Starting credit line
- $20,000
- Line after three years of on-time payments
- $40,000
- Increase
- $40,000 − $20,000 = $20,000 (a 100% rise)
- Average increase per year
- $20,000 ÷ 3 ≈ $6,667
- Loss to the lender when the account is maxed out and charged off
- Up to $40,000 on this one account
#Why is synthetic identity fraud so hard to detect?
Synthetic identities are created to look and act like a legitimate person, so they often pass initial identity checks[3]. The Federal Reserve said in 2019 that such identities can escape detection by today's identity verification and credit-screening processes[1]. After the bust-out, the Fed's toolkit observes, there may be no sign that fraud happened at all; the account simply looks like a real customer who could not pay[2].
Banks must still verify who they are dealing with. US customer identification rules require a bank to collect at least a name, date of birth, address and identification number before opening an account, and to verify identity through risk-based procedures so that it can form a reasonable belief that it knows each customer's true identity[4]. Our guides to KYC and the KYC glossary entry explain these checks. A synthetic identity is built to satisfy exactly this list, which is why it slips through.
#Who gets hurt if the person is fake?
Lenders absorb most of the direct losses, but real people can be harmed too. The Federal Reserve noted that people whose real SSNs are misused may face a time-consuming process of correcting their credit reports, and possible harms such as denial of disability benefits, rejected tax returns and inaccurate health records[1]. The Fed's toolkit also lists uses beyond simple theft, including money mule activity and the financing of trafficking and terrorism[2].
#How do lenders spot a synthetic identity?
The Federal Reserve's toolkit recommends looking at information both within individual accounts and across accounts to see whether the identity makes sense[3]. It lists these red flags[3]:
- A large amount of unsecured debt, which needs less documentation than a mortgage.
- A high number of recent credit enquiries, which can indicate an attempt to build credit quickly.
- A mismatch between the account holder's age and the length of their credit history.
- An inflated credit file depth, a suspicious mailing address or recently issued contact details.
- Across accounts: matching contact details, matching Social Security numbers or an identical digital footprint.
There is also an official data check. The US Social Security Administration (SSA) runs eCBSV (electronic Consent Based SSN Verification), a fee-based service that tells permitted financial institutions whether an SSN, name and date of birth match SSA records, with a 'yes' or 'no' answer and a death indicator where available[5]. It was created under section 215 of the Economic Growth, Regulatory Relief, and Consumer Protection Act and requires the number holder's written consent, which can be an electronic signature[5].
Common beginner mistakes about synthetic identity fraud
Thinking it has no victims
Lenders lose money, and people whose real numbers are used can face damaged records.
Believing a good payment history proves an identity is real
Building a good history is exactly how synthetic identities earn larger credit limits before the bust-out.
Assuming one ID check is enough
Synthetic identities are designed to pass initial checks; detection relies on looking across accounts and data sources.
Confusing it with account takeover
Account takeover hijacks a real person's existing account; synthetic fraud creates a new 'person' and new accounts.
Synthetic identity fraud sits at the meeting point of fraud prevention and compliance. For the opposite problem, criminals hijacking a real customer's existing account, see account takeover fraud explained.
The bottom line
Synthetic identity fraud creates a believable fake customer, often around a real identification number, and lets it earn trust before cashing out. Because the losses look like normal bad debt and there is no single victim, it is hard to spot without looking across accounts and data sources. For individuals, the practical lessons are to guard your identification number and refuse any offer to rent out your credit history.
Frequently asked questions
What is a 'bust-out'?
It is the end stage of the scheme, when the fraudster uses a synthetic identity's credit to buy high-value goods and services, then disappears without paying[1].
Can a synthetic identity use my real Social Security number?
Yes. The Federal Reserve describes synthetic identities that combine a legitimate SSN with fictional details, which can leave the real number holder correcting their credit reports[1].
Is synthetic identity fraud only a US problem?
Most public guidance on it comes from the US, where the Federal Reserve has published a mitigation toolkit[2], so this page uses US rules and examples.
How can a bank check that an SSN belongs to the applicant?
With the applicant's consent, permitted financial institutions can use the SSA's eCBSV service to check whether the SSN, name and date of birth match SSA records[5].
Sources
- Federal Reserve System white paper examines the effects of synthetic identity payments fraud — Board of Governors of the Federal Reserve System, 2019 Primary
- Synthetic Identity Fraud Mitigation Toolkit — Module 2: How Synthetic Identities Are Used — Federal Reserve (FedPayments Improvement), 2026 Primary
- Synthetic Identity Fraud Mitigation Toolkit — Module 4: Detecting a Synthetic Identity — Federal Reserve (FedPayments Improvement), 2026 Primary
- 31 CFR 1020.220 — Customer identification program requirements for banks — eCFR (US Code of Federal Regulations), 2026 Primary
- Electronic Consent Based Social Security Number Verification (eCBSV) — US Social Security Administration, 2026 Primary
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