BERLIN (Reuters) – Prosecutors in the German city of Frankfurt on Thursday said they searched apartments and offices in connection with an investigation of dividend stripping transactions.

There are seven suspects aged 46 to 55, the prosecution office said in an emailed statement, adding that they had conducted the searches on Tuesday.

The practice, known as cum-ex, typically involved cross-border trading of company shares around a syndicate of banks, investors and hedge funds to create the impression of numerous owners, each of whom was entitled to a tax rebate.