Instinet Europe has fallen victim to a spear phishing attack, giving hackers access to the broker's desktop network and compromising some client and employee information.
No details on how many clients and staffers are affected or what information was accessed has been provided but the firm is promising to work closely with victims.
However, in a statement, Instinet's parent Nomura says there has been no impact on execution and clearing systems and that regular business operations have not been disrupted.
As soon as the attack was discovered an investigation was launched, an outside cybersecurity company was brought in and authorities were notified.