The Financial Industry Regulatory Authority said on Monday it has fined Citigroup's Global Markets business $1.25 million for failing to perform proper background checks on thousands of employees between 2010 and 2017.

According to the regulator, the New York-based bank did not conduct "timely or adequate" background checks for roughly 10,400 non-registered employees. As a result, it said, the bank employed at least three individuals with criminal histories, in violation of regulatory requirements.

FINRA requires most employees at the broker-dealer firms it regulates to be finger-printed and screened for past criminal history regardless of whether the employee will be registered with FINRA to be involved in investment decisions.

Citigroup Global Markets Inc is a member of FINRA and self-reported the issue to the regulator.

While Citi had strict procedures in place to screen employees who were registered or intended to become registered, the bank had looser procedures for non-registered employees, FINRA found.

Citi, the third-largest U.S. bank by assets, neither admitted nor denied the charges. A Citi representative said the bank is pleased to have the matter resolved.