“Chase takes its responsibility to combat fraud seriously and prioritises protecting the firm and its customers to make the banking system safer,” the bank said in the court filings.
“Part of that responsibility is to hold people accountable when they commit fraud against Chase and its customers. Simply put, engaging in bank fraud is a crime.”
In one of the cases, a court filing described how on 29 August, a masked man deposited a cheque in the defendant’s Chase bank account for $335,000 (£258,300).
The court papers said the defendant then started to withdraw the money.
The cheque was eventually returned as counterfeit but the defendant still owed the bank more than $290,000, the filing added.
The amount of money kept by the defendants in the four lawsuits totalled more than $660,000, according to JP Morgan Chase’s lawyers.
Banks in the US usually allow customers to withdraw only a small fraction of the value of a cheque before it is cleared.
Last month, the Wall Street Journal reported that JP Morgan Chase closed the loophole a few days after several videos telling people about the glitch went viral on social media.
The report said the bank was investigating thousands of possible cheque fraud incidents.
