Two men have been arrested on suspicion of money laundering and breaching trademark laws.
A 47-year-old man from Elstree and a 41-year-old man from Borehamwood were arrested on Tuesday morning after police issued warrants at six addresses across Hertfordshire and Essex.
The warrants were carried out in conjuntion with representatives from firms including Nike and Adidas, along with the intellectual property office.
One woman and another two men were also arrested. All five remain in police custody.