Wohnbau Mainz

What Wohnbau Mainz does

Wohnbau Mainz GmbH is the largest housing provider in Mainz, Germany, managing approximately 11,026 residential units and 252 commercial units across the city. Founded in 1924 and headquartered at Dr.-Martin-Luther-King-Weg 20, Mainz, the company is a municipal housing company owned by the City of Mainz (10.1%), Städtische zentrale Beteiligungsgesellschaft ZBM (79.7%), and RIO Energieeffizienz GmbH & Co. KG (10.2%). It operates under a public mandate to provide affordable housing, with approximately 46% of its portfolio (~5,000 units) classified as publicly subsidized. FY2024 financials showed €99.8 million in total revenue (up €7.3 million year-over-year), a €12.6 million annual surplus, and a €921.3 million balance sheet total, with the company employing 250+ staff.

The company's core technology stack centers on the Immomio digital tenant portal (launched January 2026, replacing Immosolve) for prospective tenants, a Mieterportal for existing tenants, and the Wodis ERP system (operated by Aareon Deutschland GmbH) for property management. Its proprietary Mieterstrom (tenant electricity) model, developed through a joint venture with Mainzer Stadtwerke (Wohnen und Energie Mainz GmbH), supplies solar electricity directly from 17 photovoltaic installations—producing 584,550 kWh in 2025—at prices permanently at least 10% below local standard tariffs. Additional capabilities include a Balkonkraftwerk approval process based on the updated DIN VDE V 0126-95 standard and the AdvoSupply digital complaint system for Supply Chain Due Diligence Act (LkSG) compliance.

Revenue is generated primarily through monthly residential and commercial rents, with an average net cold rent of €7.79/m² for existing stock—approximately 38% below the Mainz market average of €12.60/m². Privately financed units average €8.22/m² and publicly subsidized units €8.90/m², with rent increases capped at 3.5% per 15 months from 2026 onward. The go-to-market is direct-to-consumer via the Immomio portal, direct tenant service, neighborhood management teams, and on-site social workers, with target customers spanning affordable-housing seekers (families, seniors, people with disabilities, voucher holders), commercial tenants (~252 units), and senior/supported living customers in dedicated 'Zuhause in Mainz' barrier-free developments. Distribution is restricted to Mainz; expansion occurs through new construction (Kommissbrotbäckerei, Große Langgasse, Ebersheim, Welschnonnengasse rooftop extension) and ancillary service lines (care, culture, mobility, energy).

Name

Wohnbau Mainz

Legal name

Wohnbau Mainz GmbH

Website

https://wohnbau-mainz.de

Company type

Private

Founded year

1924

Operating status

Operating

Headcount range

1–10 employees

Short description

Wohnbau Mainz GmbH is a municipal housing company managing approximately 11,026 residential units and 252 commercial units in Mainz, Germany. Founded in 1924, it serves affordable-housing seekers, commercial tenants, and seniors through subsidized and privately financed rentals averaging €7.79/m².

Ownership category

akta.pro rank

Product category

Affordable Housing Management

NAICS

Residential Property Managers (531311), Lessors of Residential Buildings and Dwellings (53111)

SIC

Operators Of Apartment Buildings (6513), Real Estate Agents & Managers (For Others) (6531)

akta.pro primary industry

Multifamily (Apartment) Property Management (BPAJAGAD)

akta.pro secondary industry

Affordable Housing Property Management (BPAJAGAJ)

Keywords

• Social housing management
• Affordable rental housing
• Municipal housing services
• Tenant electricity programs
• Residential property development

Headquarters

HQ city

Mainz

HQ country

Germany

HQ region

Europe

Offices1 record

Markets served

GTM type

B2C

Offering type

Services

Cost components

Personnel, Operations, Supply Chain, Infrastructure, Marketing or Sales, Technology or R&D

Revenue model

1. Residential Rent: Core revenue from approximately 11,000 residential units across Mainz. Average net cold rent of 7.79 EUR/m² for existing stock, 8.22 EUR/m² for privately financed units. Publicly subsidized housing at 8.90 EUR/m². Rental increases capped at 3.5% per 15 months for privately financed units.
2. Commercial Property Rent: Revenue from approximately 252 commercial units including retail spaces, gastronomy, and office areas.
3. Tenant Electricity (Mieterstrom): Revenue from solar electricity supplied directly to tenants from PV installations on buildings, providing cost savings vs. public grid while maintaining profitability.

Pricing tiers

Go-to-market motion2 records

Distribution channels3 records

Marketing channels6 records

Core offering

Wohnbau Mainz GmbH is the largest housing provider in Mainz, managing approximately 11,000 residential units and 252 commercial units across the city. The company develops, rents, and maintains affordable apartments with an average net cold rent of 7.79 EUR/m² (well below the local market average of 12.60 EUR/m²), offers digital tenant services through its Mieterportal and the ImmoMio housing-search platform, supplies solar-based Mieterstrom (tenant electricity) priced at least 10% below standard tariffs, and operates neighborhood management programs including senior living concepts and cultural centers.

Product overview

Wohnbau Mainz is a municipal housing company managing approximately 11,000 residential units and 252 commercial properties across Mainz. The core offering comprises housing management services including tenant portal access (Mieterportal), apartment search via ImmoMio platform, and social housing programs. The company operates through distinct product lines: standard housing management with Mieterstrom (tenant electricity) and Balkonkraftwerk approval services; new development projects including Quarters Kommissbrotbäckerei (168 units), Große Langgasse (44 units), Welschnonnengasse (16 units), and Ebersheim (73 units); social programs including 'Zuhause in Mainz' community living concept; and cultural venues such as Kulturhaus hundert11. The company also manages voluntary rent increase limits and the 'Zukunft Zuhause 55+' apartment exchange program.

Differentiator

Problem solved

Functional benefit

Products and services

• Affordable Residential Rental Housing Rental of approximately 11,000 residential apartments across Mainz, with average net cold rent of 7.79 EUR/m² for existing stock (vs. market average of 12.60 EUR/m²). Includes publicly subsidized units at 7.79 EUR/m², privately financed units at 8.22 EUR/m², and new subsidized units at 8.90 EUR/m² for middle-income households with housing entitlement certificates. Rent increases capped at 3.5% per 15 months for privately financed units.
• Commercial Property Rental Leasing of approximately 252 commercial units including retail spaces, gastronomy areas, and office/commercial premises integrated within residential neighborhoods. Includes notable tenants such as KULTURBÄCKEREI e.V. and Norbert Schön's Kulturhaus hundert11.
• Mieterstrom (Tenant Electricity) Direct supply of solar electricity from photovoltaic installations on Wohnbau buildings to tenants without passing through the public grid. Price is permanently at least 10% below the local standard electricity tariff. Currently operational in the Kommissbrotbäckerei project with 17 PV installations producing 584,550 kWh annually.
• Mieterportal (Tenant Portal) Digital self-service portal for existing tenants providing 24/7 access to contract data, documents (including operating cost statements), contact management, and online damage reporting.
• Wohnungstauschprogramm Zukunft Zuhause 55+ Voluntary apartment exchange program for tenants aged 55+ offering financial incentives including a 1,500 EUR moving bonus, full transfer of current rent per square meter to the new smaller apartment, and free renovation services. Pilot phase limited to 100 swap apartments over 24 months.
• Balkonkraftwerk-Genehmigung (Balcony PV Approval) Approval service permitting tenants to install certified balcony photovoltaic systems (plug-in solar) up to 800 VA, 3.5 A, 960 Wp modules with certified connectors. Required written approval from Wohnbau Mainz; batteries excluded.
• ImmoMio Housing Search and Registration Platform Digital housing search and registration platform for prospective tenants. Enables creation of personal search profiles, automatic notifications of matching apartment offers, and a structured application process. Integrated with Wohnbau Mainz's apartment allocation system.
• Zuhause in Mainz Community Living Concept Integrated living concept combining barrier-free apartments, neighborhood café, on-site nursing care (in partnership with simCura Pflegedienst from January 2026), and neighborhood management. Promotes community living, social participation, and intergenerational housing for people with and without disabilities.

Quantifiable outcome

• Rents 38% below market average (7.79 EUR/m² vs 12.60 EUR/m² in Mainz)
• +4 more outcomes

Named customers4 records

Segments3 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration7 records

Feature3 records

Partnerships

Nine partnerships are on record, tiered core, minor and major.

• Immomio GmbHcoreTechnology or Integration · 28 January 2026Digital tenant portal platform for apartment search and registration. Replaced Immosolve system in January 2026. 4,014 registered users within first month. Enables transparent apartment allocation with personal matching profiles.
• Regionalverband der Sinti und Roma Rheinland-NaheminorOthers · 22 January 2026Cooperation to strengthen engagement for affordable housing and promote recognition, respect, and mutual understanding. Part of Wohnbau's social responsibility commitment to diversity and anti-discrimination.
• simCura PflegedienstmajorStrategic or Co-development Partner · 14 January 2026Home care service provider starting January 2026 for 'Zuhause in Mainz' project at Karoline-Stern-Platz. Regional team of approximately 30 employees in Mainz since 2016. Offers ambulatory services including basic care, treatment care, support, and daily counseling. Also manages Café Stern as community meeting point.
• KULTURBÄCKEREI e.V.majorChannel Partner/ Reseller/ Distributor · 2 October 2025Non-profit cultural association renting 1,400 m² in Kulturhaus hundert11 as socio-cultural center. Offers events, exhibitions, workshops, and office space for Mainz's independent cultural scene. Founded 2017, funded by City of Mainz, State of Rhineland-Palatinate, and Bundeszentrale für politische Bildung.
• Norbert SchönmajorChannel Partner/ Reseller/ Distributor · 2 October 2025Experienced Mainz cultural entrepreneur and restaurateur as general lessee of Kulturhaus hundert11. Operates venues including a 600-person hall, 400-person club, and restaurant. Known for cultural venues like 'schon schön', Schick&Schön, café blumen, and SALON 3SEIN.
• MVGmeinRad GmbHmajorStrategic or Co-development Partner · 10 June 2025Joint initiative to install bike sharing stations 'meinRad' in Wohnbau neighborhoods. Stations opened at 'Am Karoline-Stern-Platz' and 'Am Hartenbergpark' with Stadträder (city bikes), Pedelecs, and E-Lastenrädern (cargo bikes). Part of sustainable mobility concept for residents.
• Wohnen und Energie Mainz GmbH (WuE)coreStrategic or Co-development PartnerJoint venture between Wohnbau Mainz and Mainzer Stadtwerke focused on climate protection through PV installations. WuE installs and operates photovoltaic systems on Wohnbau buildings, enabling the mieterstrom (tenant electricity) model. From 2024-2026, total PV capacity of approximately 1,100 kW will be installed, producing over 800,000 kWh annually.
• Mainzer Stadtwerke / Mainzer FernwärmecoreStrategic or Co-development PartnerPartnership to connect Wohnbau properties to the district heating network. Plan to connect individual quarters step by step until 2030. Initial targets: Frauenlobplatz area, Fichteplatz-Quartier, then Bretzenheim and Moselstraße areas.
• Aareon Deutschland GmbHcoreTechnology or IntegrationERP system (Wodis) operator for central data processing and property management. Data stored at KDZ Mainz.

Scale indicators11 records

Recent moves13 records

Expansion highlights6 records

Market position

Competitive moat6 records

Key risks6 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/wohnbau-mainz-gmbh
• Instagraminstagram.com/wohnbau_mainz

Compliance1 record

Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Subsidiaries2 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Wohnbau Mainz