A synthetic identity is a fictitious persona created by combining real and fake information, such as a legitimate Social Security number with a false name or date of birth. These identities are often used by cybercriminals to open bank accounts, obtain credit, or commit various forms of financial fraud. Unlike stolen identities, synthetic identities may not directly match any single real person, making them harder to detect and prevent. This type of fraud poses significant risks to financial institutions and individuals, as it can go unnoticed for extended periods.