Hartz Mountain Industries
Corporate brand
UnclaimedAmerican private real estate and investment company focused on commercial and industrial properties in the New York and New Jersey metropolitan region.
Last updated August 31, 2026
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Overview
Hartz Mountain Industries is a privately held, family-owned American real estate and investment company associated with the Stern family. Its principal business is the ownership, development, leasing, and management of commercial, industrial, retail, office, and media-related real estate, especially in New Jersey and the wider New York metropolitan area. The company is based at 500 Plaza Drive in Secaucus, New Jersey, within The Plaza at Harmon Meadow, a large retail and mixed-use complex developed and owned by the company. The company’s history is connected to the broader Hartz business established by German-born brothers Max Stern and Gustav Stern. The brothers emigrated to the United States in 1926 with a shipment of singing canaries known as Harz Rollers. They began producing bird food under the Hartz Mountain name in 1932 and expanded into the sale of birds, small animals, tropical fish, and pet-care supplies. That pet-products operation became Hartz Mountain Corporation, while the family gradually built a separate real estate business under Hartz Mountain Industries. Hartz Mountain Industries began as an ancillary or personal real estate activity for the Stern family and became a substantial operating enterprise. It constructed its first speculative industrial building in Bayonne, New Jersey, in 1966. The company later made a major investment in the New Jersey Meadowlands by acquiring approximately 750 acres of land. This acquisition helped establish the company as a significant regional property owner and developer in an area undergoing industrial, commercial, and infrastructure transformation. The company’s portfolio has included industrial buildings, office properties, retail centers, development land, and specialized facilities. Its holdings have included The Plaza at Harmon Meadow in Secaucus, facilities associated with MLB Network, and property connected with television broadcasting operations, including land formerly used by WWOR-TV. By October 2021, the company was reported to own more than 250 properties across New Jersey and other parts of the East Coast, along with more than 1,800 acres of land near Manhattan. Hartz Mountain Industries is distinct from Hartz Mountain Corporation, the pet-products company that once formed part of the same family-controlled business system. Hartz Mountain Corporation was sold to the investment group J.W. Childs and certain members of its management in 2000, later became owned by Sumitomo Corporation in 2004, and in 2011 Unicharm acquired a 51 percent interest. Although the pet-products company retained the Hartz Mountain name and continued to occupy space in Secaucus, it became a separate corporate entity and a tenant of Hartz Mountain Industries. Leonard N. Stern, son of Max Stern, joined the family enterprise in 1959 and became the owner, chairman, and chief executive officer of Hartz Mountain Industries. The company remains privately held and does not publish the level of financial reporting associated with a listed real estate investment trust. Its positioning is that of a long-term, relationship-oriented property owner and developer with a concentrated regional portfolio, rather than a consumer-facing property brand or publicly traded real estate platform.
History
Hartz Mountain Industries developed from the business interests of Max and Gustav Stern, German immigrants who arrived in the United States in 1926 with thousands of Harz Roller singing canaries. In 1932, the brothers began manufacturing bird food under the Hartz Mountain name. Their business expanded into the distribution of canaries, parakeets, hamsters, tropical fish, and related supplies. Over time, Hartz products and pet departments reached supermarkets and retailers in the United States, Canada, and the United Kingdom. The pet-products operation became known as Hartz Mountain Corporation. Although the pet business and the real estate business shared the Hartz Mountain identity and a common family history, they developed into distinct operations. Hartz Mountain Industries emerged when the Stern family began treating real estate as a significant business activity rather than merely an adjunct to the pet-products company. Its first speculative industrial building was constructed in Bayonne, New Jersey, in 1966. The company’s most consequential early real estate expansion came through the acquisition of approximately 750 acres in the New Jersey Meadowlands. The Meadowlands offered proximity to Manhattan, major transportation routes, and a large supply of developable land. Hartz Mountain Industries built a regional portfolio around these advantages, acquiring and developing industrial, office, retail, and other commercial properties. The company eventually became one of the prominent private landowners and developers in the New Jersey Meadowlands and surrounding areas. A key part of the company’s operating model has been long-term ownership and leasing rather than rapid asset turnover. Its portfolio has included The Plaza at Harmon Meadow in Secaucus, where the company is headquartered, as well as office and industrial facilities, retail space, and property used by media and broadcasting organizations. The company has also owned the studios used by MLB Network and land associated with WWOR-TV broadcasting facilities before those operations were consolidated with WNYW in Manhattan. The separation of the pet-products business accelerated in the early twenty-first century. In 2000, Hartz Mountain Corporation was sold to J.W. Childs and selected members of its management. Sumitomo Corporation acquired the pet-products company in 2004, and Unicharm purchased a 51 percent stake in 2011. The pet-products company retained the Hartz Mountain name and continued operating from Secaucus, where it became a tenant of Hartz Mountain Industries. These transactions did not transfer Hartz Mountain Industries’ real estate portfolio to the pet-products buyers. Leonard N. Stern, Max Stern’s son, joined the family company in 1959 and became its owner, chairman, and chief executive. Under his leadership, Hartz Mountain Industries continued to operate as a private family-controlled real estate enterprise. Constantino T. Milano has served as president and chief operating officer, and Edward Stern has also worked for the company. By October 2021, public descriptions of the business indicated that it owned more than 250 properties in New Jersey and elsewhere along the East Coast, together with more than 1,800 acres of land near Manhattan. Today, Hartz Mountain Industries is best understood as a regional property owner, developer, and landlord rather than as a pet-products brand. Its business is concentrated in income-producing and development-oriented real estate, with particular strength in New Jersey and the New York metropolitan area. Because it is privately held, detailed financial results, valuation information, and a complete property-by-property portfolio are not generally disclosed in public sources.
- 2021
Portfolio reported at more than 250 properties
[1]Public descriptions stated that Hartz Mountain Industries owned more than 250 properties across New Jersey and the East Coast, as well as more than 1,800 acres near Manhattan.
- 2011
Unicharm acquired a 51 percent stake in Hartz Mountain Corporation
[1]Unicharm purchased majority ownership of the pet-products company from Sumitomo Corporation.
- 2004
Sumitomo acquired Hartz Mountain Corporation
[1]The separate Hartz pet-products business was acquired by Sumitomo Corporation.
- 2000
Pet-products business sold to J.W. Childs
[1]Hartz Mountain Corporation was sold to J.W. Childs and selected management, separating the pet-products operation from Hartz Mountain Industries.
- 1966
First speculative industrial building constructed
[1]Hartz Mountain Industries began its documented real estate development activity with a speculative industrial building in Bayonne, New Jersey.
- 1959
Leonard N. Stern joined the family business
[1]Max Stern’s son entered the family enterprise and later became the owner, chairman, and chief executive of Hartz Mountain Industries.
- 1932
Bird-food manufacturing began under the Hartz Mountain name
[1]The Stern brothers began producing bird food, creating the consumer-products business that later became Hartz Mountain Corporation.
- 1926
Max and Gustav Stern immigrated to the United States
[1]The brothers arrived from Germany with a shipment of Harz Roller singing canaries, laying the foundation for the family’s later Hartz business.
Products and positioning
A private, family-controlled regional real estate owner and developer with a substantial portfolio in New Jersey, the New York metropolitan area, and the broader East Coast.
Commercial real estate
Commercial and office properties
Hartz Mountain Industries owns and leases office and commercial properties in New Jersey and the New York metropolitan area. These assets provide space for corporate tenants, media organizations, retailers, and other businesses. The company’s headquarters at The Plaza at Harmon Meadow reflects its role as both property owner and occupier within a larger mixed-use commercial complex.
Industrial real estate · 1966
Industrial properties
Industrial development was an early foundation of the company’s real estate strategy. Beginning with a speculative industrial building in Bayonne in 1966, Hartz Mountain Industries expanded its portfolio to include industrial buildings and related land holdings positioned near New York-area transportation infrastructure and population centers.
Retail and mixed-use real estate
The Plaza at Harmon Meadow
The Plaza at Harmon Meadow is a major retail and commercial complex in Secaucus, New Jersey. It also contains the company’s headquarters at 500 Plaza Drive. The development illustrates Hartz Mountain Industries’ approach of combining property ownership, leasing, and large-scale commercial development in the Meadowlands region.
Specialized commercial real estate
Media and broadcasting facilities
The company’s holdings have included specialized facilities used by media and broadcasting organizations. Identified examples include studios used by MLB Network and land associated with former WWOR-TV broadcasting operations, demonstrating the portfolio’s exposure to institutionally oriented and media-related properties.
Brand decisions
2011
Unicharm’s majority investment in Hartz Mountain CorporationM&ABackground
Hartz Mountain Corporation remained a separate pet and household-products business after the earlier sale to Sumitomo.
Action taken
Unicharm acquired a 51 percent ownership interest from Sumitomo Corporation.
Aftermath
The transaction further separated ownership of the pet-products company from Hartz Mountain Industries, whose core business continued to be regional real estate.
2004
Sale of the separate pet-products company to SumitomoM&ABackground
Following the 2000 divestiture, Hartz Mountain Corporation operated as a separate pet-products company.
Action taken
Sumitomo Corporation acquired Hartz Mountain Corporation.
Aftermath
The pet-products company retained the Hartz Mountain name and continued occupying premises associated with Hartz Mountain Industries.
2000
Divestiture of Hartz Mountain CorporationM&ABackground
The Stern family’s pet-products operation had grown into a business distinct from the family’s real estate activities.
Action taken
Hartz Mountain Corporation was sold to J.W. Childs together with selected members of its management, while Hartz Mountain Industries remained the Stern family’s real estate business.
Aftermath
The pet-products company continued using the Hartz Mountain name and later changed ownership again, while Hartz Mountain Industries retained ownership of the Secaucus facilities occupied by the pet business.
Sources1 sources
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