For a large multifamily portfolio the platform question is settled by four workloads, not by feature lists: statutory accounting and the Nebenkosten settlement, maintenance and work orders across many buildings, owner and tenant communication, and reporting across the whole portfolio. Housing-industry ERP systems such as Aareon Wodis, Haufe wowinex and axera, DOMUS and iX-Haus carry holdings in the thousands of units. Mid-market administrator software such as Immoware24, hellohousing and immocloud typically covers somewhere between 50 and 5,000 units. A portfolio layer sits above whichever of those you run, for the questions the accounting system was never built to answer. The useful work is figuring out which band you are actually in.
What "large" actually changes
Portfolio size does not scale smoothly. It moves through thresholds, and at each one a different thing becomes the bottleneck.
Up to roughly 200 units, the constraint is the annual Nebenkostenabrechnung. Everything else fits in a spreadsheet and a shared drive, which is why so many administrators run that way far longer than they admit. Around 500 to 1,000 units the bottleneck moves to operations: work orders, contractor coordination, inspection records and the sheer document volume. Somewhere past 2,000 units it moves again, to accounting depth, clean separation between mandates and legal entities, and the audit trail an external auditor or a municipal owner will ask for.
Two structural facts matter more than the raw unit count. The first is the mix of WEG administration and Mietverwaltung, because WEG management carries statutory duties, resolution records and deadlines that pure rental management does not. The second is how many legal entities the portfolio spans. Ten buildings in one GmbH is a different software problem from ten buildings across six property companies with different owners, and it is usually the entity count, not the unit count, that breaks the cheaper tools.
The four workloads that decide the platform
Statutory accounting and the Nebenkosten settlement. This is the non-negotiable core. At scale you need per-mandate ledgers, correct allocation keys, prepayment tracking, dunning, and a settlement run that survives being challenged by a tenant. This workload alone rules out most general-purpose tools, and it is the reason large holders keep a dedicated Wohnungswirtschaft system even when they dislike it.
Maintenance, work orders and inspections. Across a large multifamily holding this is the daily operational reality: a defect is reported, a contractor is assigned, a cost lands, a warranty period runs. The question to ask is whether work orders are a proper object with status, assignment, cost and history, or a free-text field bolted onto the building record. The difference shows up the first time somebody asks what a given building actually cost in repairs last year.
Owner and tenant communication. Large portfolios generate correspondence at a rate that email cannot organise. Owner statements, resolution notices, defect updates and settlement dispatch all need to be traceable back to the unit and the period. This is the workload that portal products such as casavi target specifically, and it is often the first thing bolted onto an older ERP rather than replaced.
Reporting across the portfolio. Occupancy, arrears, maintenance spend per building, capital expenditure against plan, and the same figures rolled up across entities. Accounting systems answer this for one mandate at a time and struggle to answer it across a whole holding, which is why so many large administrators still assemble the board pack in Excel every quarter.
The categories of platform
| Category | Typical size | Examples | Strongest at | Where it strains |
|---|---|---|---|---|
| Housing-industry ERP | 2,000 units and up | Aareon Wodis, Haufe wowinex and axera, DOMUS, iX-Haus | Accounting depth, mandate separation, audit trail | Cost, project length, day-to-day usability |
| Mid-market administrator software | roughly 50 to 5,000 units | Immoware24, hellohousing, immocloud | WEG and rental accounting, owner portals, fast onboarding | Cross-entity reporting, development projects |
| Communication and service layer | any | casavi | Tenant and owner communication, defect intake | Not an accounting system; complements one |
| Corporate real estate module | large corporates | SAP RE-FX | Sits inside an existing SAP landscape | Overkill unless SAP is already the standard |
| Portfolio and development layer | any, alongside the above | REPM | Portfolio reporting, development projects, operations | Not a replacement for statutory accounting |
What each is actually good at
Aareon Wodis is built for housing companies and cooperatives with large residential holdings, and the newer Yuneo line moves that into the cloud. If you are a municipal housing company or a Genossenschaft with several thousand units, this is the category you are being sold into, and mostly for good reason: the accounting and mandate model is deep.
Haufe covers a range, from PowerHaus for established professional administrators through wowinex for housing companies to the cloud-native axera. The breadth is real, but it means the product you are shown depends heavily on which segment the sales conversation starts in.
DOMUS and iX-Haus (CREM SOLUTIONS) both sit at the professional and commercial end. DOMUS 4000 has a long history with larger WEG administrations; iX-Haus is common where commercial and mixed-use assets are in the portfolio alongside residential.
Immoware24 is frequently the strongest answer for a professional administrator who is genuinely large but does not want an ERP programme. It handles substantial data volumes, dunning and document management in one cloud system, and it is often where administrators land after outgrowing lighter tools.
hellohousing and immocloud are lighter and cleaner, and are a better fit below the thousand-unit mark than above it. If you are evaluating them for a genuinely large holding, test the settlement run and the document volume before anything else.
casavi is not competing with any of the above on accounting. It is a communication and service layer, and large administrators commonly run it alongside an ERP rather than instead of one.
Where a portfolio layer fits, and where it does not
An honest boundary is worth drawing here, because it is the thing most comparison articles blur. REPM is not a Wohnungswirtschaft ERP. It does not run your WEG accounting, and it will not produce the statutory Nebenkosten settlement. If those are your problem, the answer is one of the systems above, and you should buy one.
What a portfolio layer answers is the set of questions that sit above the accounting system. What is the whole holding worth and how is it performing, across every legal entity at once. Which buildings are consuming the maintenance budget. What is the capital expenditure plan against actual, by building and by cost group. And, for the many holders who also build, how the development pipeline connects to the standing portfolio it will eventually join, with the DIN 276 cost plan on the same record as the finished asset.
That is REPM's actual position: it runs on Microsoft Dataverse, inside your own tenant, and it is strongest for holders whose portfolios span several entities, who develop as well as hold, and whose IT would rather extend a Microsoft platform than adopt a tenth vendor. For a pure WEG administrator with one legal entity and no development activity, it is the wrong tool, and we would rather say so than sell it. The comparison against classic administrator software sets out that boundary in more detail.
An evaluation checklist for a large portfolio
- Run the Nebenkosten settlement for your largest and messiest building during the trial, not a demo property. Allocation keys and vacancy periods are where settlements break.
- Ask how mandates and legal entities are separated, and what a user who should only see one entity actually sees.
- Check whether a work order is a first-class record with status, assignee, cost and history, or a note field.
- Ask for a report that spans every entity at once. If the answer involves exporting to Excel, that is your future quarterly routine.
- Test the document volume. Load a realistic year of invoices and correspondence for one building and see what search feels like.
- Establish what happens to your data if you leave, in a usable format and on what notice. Vendor risk is a real cost at this size.
- Confirm who does the migration, how long it takes and what it costs. For several thousand units this is the dominant number in year one, not the licence fee.
Choosing by portfolio size
| Portfolio | Sensible starting point |
|---|---|
| Under 200 units | Mid-market administrator software, or a spreadsheet if the tipping point has genuinely not arrived |
| 200 to 1,000 units | Immoware24, hellohousing or immocloud; add a communication layer if owner correspondence is the pain |
| 1,000 to 5,000 units | Immoware24 or DOMUS; consider a portfolio layer once reporting spans several entities |
| Over 5,000 units | Aareon Wodis, Haufe wowinex, iX-Haus; a portfolio layer above it for cross-entity and development reporting |
| Holding and developing together | Keep the accounting system, add a layer that carries projects and standing assets on one model |
Test it against your own portfolio
No comparison table settles this, including the one above. What settles it is loading your own worst building into a trial and running the settlement, the work orders and the reporting question you actually get asked. If a platform survives that, it will survive your portfolio. REPM Lite is the free self-serve trial: add a property, split it into units, record leases and see what the portfolio view gives you, with no card and no sales call. If your accounting system already answers everything above, keep it, and we will say so on the call. What we see more often is that it answers the first workload well and the fourth not at all. See what REPM does for property managers, or start in the free trial.