A Wauwatosa man and his current employer are being sued for misappropriating trade secrets after the man allegedly shared classified information taken from his previous job.
Milwaukee-based HellermannTyton Corp., along with employee Thomas Marsden, have been named as defendants in the lawsuit.
A complaint was filed on behalf of Penn Engineering & Manufacturing Corp., the parent company of Heyco Products Corp., in U.S. District Court for the Eastern District of Wisconsin last week.
Danboro, Pennsylvania-based Penn Engineering makes a variety of fastening solutions and installation equipment for several industries.
Toms River, New Jersey-based Heyco is a subsidiary of Penn Engineering that makes wire management products.
Marsden began working at Heyco in August 2015 and voluntarily resigned in February 2025. At the time of his resignation, he served as Heyco’s director of marketing and renewable energies. Through this role, Marsden had access to Heyco’s confidential information and trade secrets. Because he had access to this information, Marsden entered into a confidentiality agreement with Heyco.
Shortly after resigning from Heyco, Marsden allegedly began working at HellermannTyton. Before submitting his resignation, Heyco alleges Marsden sent several emails containing trade secrets and confidential information to his personal email address.
This information allegedly included, among other things, a detailed contact list with hundreds of Heyco customers; a detailed project lead database; various digital images of products; a list of target customers; and more.
On Feb. 16, Marsden allegedly attached a USB device to his company computer, in violation of company policy.
“Given the sensitivity of the data that Marsden took without business purpose or authorization, (Heyco) immediately contacted Marsden and HellermannTyton regarding Marsden’s conduct and made repeated attempts to recover from him all company documents and information he took or in his possession, verify whether and how that information had been shared with third parties, obtain information relating to the encryption on his company-issued computer, and secure his written assurances that he had not taken and did not possess any other property,” according to the lawsuit.
Heyco claims Marsden has failed to return any documents or classified information and that HellermannTyton continues to employ him.
Heyco claims Marsden has breached the confidentiality agreement he signed with the company in September 2016.
Heyco also alleges HellermannTyton has knowledge of the confidentiality agreement but continues to employ Marsden in a similar role to the one he held at Heyco.
Heyco is suing Marsden for two counts of breach of contract and breach of fiduciary duty. The company is suing HellermannTyton for tortious interference with a contract. Both parties are also facing three charges of misappropriating trade secrets.
Heyco is seeking an order from the court to prevent Marsden from violating his confidentiality agreement, along with an unspecified amount in damages.
“While we will not comment specifically on the allegations in the pending litigation, we believe that we will be able to establish that many of the allegations are intentionally salacious, misleading and unsupportable,” said Marsden’s attorney, Sally Piefer, in a statement issued to BizTimes Monday evening.
Piefer works at Milwaukee-based Lindner & Marsack, which is the law firm representing Marsden in this case.
HellermannTyton, through a company representative, declined to comment on the case Monday, saying the company does not comment on pending litigation.
Representatives from Penn Engineering did not immediately respond to a request for comment Monday.
