First they promised rent reductions, now they've announced increases: The Left Party faces a credibility test

Lower rents, high costs: The crucial calculation behind Berlin's socialization plans

Berlin housing market: Why socialization alone won't solve the rental crisis

Can the socialization of large housing stocks lower rents in Berlin – or, more importantly, curb their further increases? This question lies at the heart of a debate where political expectations and economic realities are increasingly clashing. In the program "Bosetti Late Night," the Left Party chairwoman, Ines Schwerdtner, did not promise any binding rent reductions. Instead, she pointed to maintenance costs and a possible annual rent increase cap of no more than two percent. This would not automatically mean a rent reduction or a halt to all increases, but rather a limitation on their magnitude.

Whether such a regulation will bring noticeable relief to Berlin households depends on far more than just the change of ownership. Crucial factors include the amount of compensation, the financing, the condition of the buildings, and the costs of repairs and modernizations. Furthermore, transferring existing apartments does not create additional living space. It can change how properties are managed and rents are set – but it doesn't solve the problem of apartment seekers facing a scarce and expensive supply.

A closer look at Berlin's rental data, the potential financing costs, and the differing interests of existing tenants and those seeking housing reveals what's crucial: socialization can be a housing policy instrument. However, whether it actually provides social relief depends on a comprehensive analysis – and on which measures it complements.

Change owners, perpetuate the housing shortage? Why the bottom line is ultimately more important than the slogan

Berlin's debate on the socialization of large housing stocks has reached a crucial juncture: the question of whether a politically organized change of ownership will actually lead to lower rents or primarily limit their further increases. There is a significant difference between these two objectives. For a household already living at its financial limit, a slower increase in rents is certainly better than a rapid one. However, this does not provide immediate relief.

The Left Party leader, Ines Schwerdtner, highlighted this limit on the program "Bosetti Late Night." She did not promise any binding rent reductions for individual households, citing the necessary maintenance costs. At the same time, she outlined an annual rent increase cap of a maximum of two percent, which should also apply to social housing. Strictly speaking, such a cap is neither a guarantee of stable rents nor an announcement that every rent must necessarily increase by exactly two percent each year. It allows for increases but aims to limit their extent.

This shifts the focus of political debate. The question of ownership is no longer the sole focus, but rather the viability of a management model. The crucial factor is whether, after a takeover, the rental income will be sufficient to cover ongoing costs, repairs, modernizations, and financing without placing an undue burden on public budgets or requiring permanent additional public funding.

A sober economic assessment therefore leads neither to blanket rejection nor blanket approval. Socialization can change the use of surpluses, rental strategies, and the allocation of apartments. However, it does not initially create additional housing, nor does it eliminate the costs of building operation. Its benefits depend on the conditions under which it is implemented and which other housing policy measures it complements or displaces.

The political conflict begins with the meaning of the promise of relief

The current controversy is not merely a dispute over an unfortunate choice of words. It concerns the expectations associated with a particularly far-reaching political instrument. Those who want to remove large housing stocks from the private sector's profit motive understandably associate this with the prospect of better conditions for the people living there.

Previous party statements explicitly established a link between socialization and falling rents. At the same time, saved dividends were presented as potential financial leeway for lower rents or improved maintenance. If the practical implementation subsequently amounts primarily to limited increases, a discrepancy arises between the political message and its operational implementation that requires explanation.

Three objectives must be distinguished here. A nominal rent reduction means that the monthly euro amount payable actually decreases. Stabilization means that it remains unchanged. Dampening simply means that it increases less sharply than would be expected under other conditions.

All three can be relevant to social policy. However, they are not interchangeable. Political communication becomes particularly problematic when the population expects an immediate reduction, while the financial model only allows for a long-term limitation of the increase.

Conversely, it would be equally simplistic to treat every permissible rent increase as proof of the failure of public management. If the costs for skilled trades, personnel, and building technology rise, even a non-profit landlord may need higher income. The crucial question then becomes whether the increase is necessary, appropriate, and socially acceptable.

Schwerdtner's reference to maintenance thus identifies a real economic problem. However, it does not solve the political task of precisely explaining what relief can be achieved under which conditions.

The Berlin rental crisis consists of several very different markets

The Berlin housing market cannot be described by a single rent figure. It is particularly important to distinguish between existing tenancies, newly signed contracts, and publicly advertised properties. These categories overlap but represent different segments of the market.

The average advertised rent in 2024 was €15.74 per square meter (net rent excluding utilities). This was 12.5 percent higher than the previous year. A median rent of €15.78 was projected for 2025. After the strong increases in the preceding years, this represented a near-stagnation, albeit at a significantly higher level. Compared to €9.00 per square meter in 2016, the increase by 2025 amounted to approximately 75 percent.

These figures do not represent the average rent for all Berlin households. The median is the middle value of the analyzed listings: half are below it, half above. It primarily shows the prices that apartment seekers in the surveyed listing segment are confronted with.

The differences between the submarkets are illustrated by a comparison with the market-rate rents for new rental contracts offered by companies organized within the BBU (German Association of Housing and Real Estate Companies). These averaged €8.59 per square meter between July 1, 2023, and June 30, 2024, significantly lower than publicly recorded asking rents. However, these figures are derived from different populations and therefore should not be used as a direct price comparison for identical apartments.

This distinction is crucial for economic analysis. A change of ownership can initially protect the people already living in the affected apartments. However, those moving to Berlin for the first time, seeking a smaller apartment after a separation, or needing to relocate due to a job change, require access to available housing options.

A successful policy regarding existing housing stock therefore does not yet answer the question of how to accommodate additional households. This is precisely where the limit of a debate that focuses primarily on the rents of already rented apartments lies.

Two percent can mean relief – but not for every household

An annual rent increase of two percent seems manageable at first glance. However, its actual significance depends on the initial rent, income, and the time period under consideration.

With a monthly net rent of €600, a two percent increase initially means an additional €12 per month. The annual increase amounts to €144. For a financially secure household, this is usually manageable. For a household without savings, however, even this amount can be significant.

Even more important is the development over several years. Repeated increases build on the steadily rising rents. What starts as a small annual increase therefore becomes a permanent additional burden. A rent cap should therefore not be confused with a permanently low rent level.

At the same time, a distinction must be made between nominal and real developments. If incomes and the general price level rise faster than rents, the relative burden on renters can decrease even though the total amount in euros increases. If incomes lag behind, the burden increases even with a formally moderate rent increase.

Therefore, the rent-to-income ratio is more meaningful for assessing social impact than the rate of change alone. It describes what proportion of disposable income must be spent on housing. An identical rent can have very different consequences for different households.

In addition, there is the total rent including utilities. Even a limited net rent does not completely protect against rising heating costs or higher operating expenses. Therefore, an apartment can become more expensive overall even if the base rent remains unchanged.

The political focus on two percent is therefore insufficient. A viable relief strategy must take into account the development of overall housing costs and the economic capacity of the affected households.

A new owner changes goals, but not the need for repairs

The strongest economic rationale behind socialization is that rental income should no longer primarily serve a private profit strategy. Instead, surpluses could remain in the housing stock, finance social rent regulations, or be used for additional investments.

This idea is fundamentally understandable. A company that doesn't have to make distributions to private shareholders can set different priorities. For example, it can accept a lower return, plan for the long term, or focus more on preserving affordable housing.

However, the saved dividend payout is not automatically the same as the financial leeway for rent reductions. Part of the surplus may be needed for repair reserves, new investments, or debt repayment. Furthermore, a change of ownership may incur new financing costs.

The physical condition of the buildings also remains unchanged. A roof in need of repair will not become watertight simply by being transferred to public ownership. A worn-out heating system will not become more efficient. Necessary work can be postponed, but it cannot be permanently avoided free of charge.

Realistic management must therefore differentiate between ongoing maintenance and major modernizations. Regular repairs maintain usability. Extensive renovations, on the other hand, can also change energy efficiency, accessibility, or technical equipment.

Anyone who wants to keep rents permanently low needs a sound financing plan for both. Otherwise, hidden debt on the building stock will arise: work neglected today will lead to higher costs, greater damage, or worse living conditions later.

The crucial question, therefore, is not whether a public owner can forgo returns. It is how much can actually be saved after fully considering all long-term necessary expenditures.

The compensation determines the economic leeway

The main cost factor in a socialization is the compensation of the previous owners. The amount of this compensation determines what financing is needed and what proportion of future rental income will be tied up in interest and principal payments.

The legal debate must be distinguished from the economic one. The majority of the Berlin expert commission appointed in 2023 considered the socialization of large housing stocks to be legally permissible in principle. However, this does not imply either a final judicial confirmation of a specific law or a binding compensation amount. Even a fundamentally permissible socialization requires appropriate compensation; the conditions under which this may fall below market value remain a crucial question of policy.

Economically, the connection is clear: the higher the compensation, the more difficult it becomes to simultaneously guarantee low rents, adequate maintenance and full financing from current income.

A low settlement can increase financial flexibility, but it can also trigger more intense legal disputes. A high settlement can defuse certain conflicts, but it places a greater burden on ongoing expenses.

This creates a tension between legal protection, financial viability, and socio-political demands. None of these dimensions can be seriously considered in isolation.

A politically determined maximum amount therefore does not replace a sound assessment. It initially only describes how much is to be spent. Whether the affected assets can be legally transferred for this amount and subsequently managed in an economically viable manner must be examined separately.

It is equally insufficient to simply point out that real estate retains its value in the long term. A building that is valuable in the long run can cause significant liquidity problems in the short term if high financing costs coincide with limited current income.

A model calculation shows why the interest rate question is so important

How sensitive the financing can be can be illustrated with a simplified calculation. This is explicitly not an actual business plan, but rather a scenario to put the magnitude of the issues into perspective.

Let's assume a portfolio of 100,000 apartments needs to be refinanced with ten billion euros. At an interest rate of three percent, this would initially result in annual interest costs of 300 million euros. Distributed across the entire portfolio, this would average 250 euros per apartment per month.

At five percent, the initial annual interest costs would be 500 million euros. That would correspond to approximately 417 euros per apartment per month. In both cases, repayment, administration, maintenance, and other expenses would not yet be taken into account.

However, this does not mean that these amounts must be added to the existing rents in full. Private landlords also have financing costs and already use part of their income for debt service and profit. A complete calculation must therefore compare the current cost structure with the future one.

The model calculation shows something different: Even a few percentage points difference in the interest rate can significantly alter the available financial flexibility. The loan term and the repayment agreement are equally important. All other things being equal, a longer loan term reduces the annual repayment burden but extends the financial commitment.

Financing with expiring fixed interest rates introduces additional risks later on. Those who secure favorable terms today don't automatically know what the conditions will be for refinancing in ten or twenty years.

A robust model therefore requires stress tests. It must also function, or allow for clearly defined adjustments, if interest rates rise, repairs become more expensive, or revenues fall short of expectations.

Public funding is not free money

A common argument in favor of public takeovers is that government-backed financing can be cheaper than raising capital for private companies. This can be true under certain conditions. However, a favorable interest rate does not eliminate risk.

When public guarantees reduce financing costs, the government assumes at least a portion of potential losses. This risk does not necessarily lead to an immediate expenditure, but it remains economically relevant.

The same applies to the claim that a project does not burden the budget because it is financed through a separate company. The organizational structure alone is not the deciding factor. What matters is who is actually liable in the event of a funding shortfall.

If a publicly controlled housing company cannot meet its obligations from its revenues, several adjustment options are generally available: higher revenues, lower expenditures, longer repayment periods, or additional support. Each of these options has distributional effects.

Higher rents burden residents. Reduced maintenance negatively impacts the quality of housing and future generations. Additional public funds compete with other priorities. Longer-term financing postpones obligations.

A serious analysis must disclose these alternatives. It must neither treat every loan as irresponsible nor confuse financing outside the core budget with being economically cost-free.

Especially in a long-term project, transparency is more important than presenting the first few fiscal years in the most favorable light possible.

Keeping existing housing affordable does not replace the need for additional living space

The biggest structural limitation of socialization lies on the supply side. If an existing apartment is transferred to a different owner, this does not initially create any additional living space.

This does not mean that the change of ownership is ineffective. It can influence the rent, the long-term nature of tenancies, and the criteria used to allocate vacant apartments. However, it does not directly change the number of available apartments.

For a city with a tight market, this distinction is crucial. Socially responsible management of existing housing and increasing supply address different problems.

In 2024, a total of 15,362 apartments were completed in Berlin. This was 3.8 percent fewer than in the previous year. This figure illustrates that new construction is taking place under difficult conditions; however, it alone does not provide a complete picture of the housing shortage in individual districts and household groups.

New construction requires land, planning, financing, construction capacity, and infrastructure. Even a clear political prioritization therefore does not immediately lead to ready-to-occupy apartments.

Conversely, not every new building can immediately solve the current problems of low-income households. High construction costs can mean that new apartments can initially only be offered economically at high rents. Without subsidies or other favorable conditions, affordable housing does not automatically emerge.

An effective strategy must combine both levels: preserving affordable existing housing and creating additional housing. If one level is pitted against the other, housing policy remains incomplete.

Whether investors build less depends on the specific rules

Among the most significant objections to socialization plans is the concern that private investors would be deterred. This could lead to less new construction and, in the long term, higher housing costs.

This effect should be taken seriously as a risk, but not assumed to be an inevitable outcome. Investment decisions depend on many factors: expected rents, land costs, construction costs, financing, permitting time, and the predictability of legal frameworks.

Political intervention can increase perceived uncertainty. If investors fear that further portfolios could be affected in the future or that the rules might be changed retroactively, they may demand higher returns or prefer other locations.

However, the consequences depend on how clearly the scope of application is defined. A narrowly defined, transparently regulated approach is to be assessed differently from an economic perspective than a permanently open reservation of the right to intervene.

The distinction between existing and newly constructed apartments is also important. If new construction investments are treated differently under the law than certain existing properties, this can limit the impact on new projects. Whether this is sufficient depends on the credibility and consistency of the regulation.

It would be equally wrong to assume the opposite: that public ownership automatically leads to a larger supply. Publicly owned companies also have to finance and implement projects. If a large portfolio consumes a significant portion of their financial and organizational capacity, this can hinder other investments.

The relevant question, therefore, is not whether private or public owners generally build better. The decisive factor is which institutional conditions actually enable the creation of additional, needs-based housing.

The biggest distribution issue is between existing tenants and those looking for apartments

Socialization can be particularly beneficial to households already living in the affected apartments. They may receive a more reliable rental income path, stronger social protections, or better opportunities for participation.

People outside this pool of housing, on the other hand, only benefit indirectly or if they gain access to a vacant apartment. This creates a distribution problem that is often underestimated in political debate.

A family with a favorable long-term lease can continue to pay particularly low rent despite rising incomes. A lower-income household currently searching for an apartment, on the other hand, may face significantly higher prices.

This is not an argument against protecting existing tenancies. However, it shows that affordable existing rents do not automatically ensure a needs-based distribution.

If a publicly controlled housing stock is to fulfill specific social functions, the rules for new tenancies become particularly important. Income levels, household size, special urgency, and suitable apartment sizes can all be taken into account.

Mobility within existing housing stock also deserves attention. Those living in a large, affordable apartment often have little financial incentive to move to a smaller, but more expensive one. A successful apartment swap can help to make better use of existing space, provided it doesn't involve significant disadvantages in terms of rent.

The social quality of a housing model is therefore not solely measured by the average rent. It also depends on who has access and whether the apartments meet the actual needs of the households.

The amount of rent including utilities determines everyday life, not the political indicator

For people, it's not just the net rent that matters at the end of the month. What's crucial is the total cost of living.

Energy, building cleaning, maintenance, and other operating costs that can be passed on to tenants can increase the burden, even if the base rent rises only slowly. A policy that focuses solely on the base rent can therefore miss the true financial situation.

The balance between energy-efficient renovations and short-term affordability is particularly challenging. Investments in building envelopes and heating technology can reduce energy consumption. However, they initially incur costs and do not automatically lead to a lower overall cost in every case.

Whether a measure has a financially beneficial effect on the residents depends, among other things, on the investment costs, subsidies, cost distribution, and the actual savings achieved. Heating habits and energy price trends also play a role.

This presents a challenging management task for public or community-based entities. Simply renovating as much as possible is not enough. Investments must be technically sound, time-coordinated, and socially sustainable.

A long-term perspective can be helpful. By bundling measures and planning them in a timely manner, unnecessary duplication of effort can be more easily avoided. In contrast, a remediation policy that only reacts to acute damage is often more difficult to plan.

Therefore, success should not only be measured by the development of the net rent, but also by living quality, energy consumption and total monthly costs.

Good public administration needs more than a social mission

Public ownership is not an automatic guarantee of quality. Even a publicly funded portfolio requires professional management, clear responsibilities, and effective oversight.

A social mission can lead to conflicting objectives. Low rents, quick repairs, high climate protection standards, additional new construction, and a balanced budget are all understandable goals. However, they cannot all be maximized simultaneously under all circumstances.

Therefore, it is essential to define priorities and how deviations from targets will be disclosed. A company should not be judged solely on whether it charges the lowest possible rent in the short term. Equally important is its ability to maintain its portfolio in the long term.

Meaningful reporting should therefore consider rent trends, maintenance expenses, repair times, investments, and financing risks together. The development of renovation needs is particularly important. A favorable annual result is of little significance if necessary work is merely postponed.

Tenant participation also requires clear structures. It allows them to contribute local knowledge, identify conflicts early on, and make priorities more transparent. At the same time, technical, legal, and financial decisions must remain viable.

Democratic control and professional management are not opposites. They fulfill different functions. Control sets goals and monitors results; management organizes the economic and technical implementation.

Without this separation, there is a risk that short-term political interests will override long-term building management.

Every euro invested has a housing policy alternative

A comprehensive assessment must not only ask whether nationalization is financially feasible. It must also examine whether the same public funds could achieve a greater social impact through other means.

This question concerns opportunity costs: those who tie up money, credit lines and administrative capacity for a specific measure cannot simultaneously use them fully for other tasks.

Alternatives include subsidized new construction, the acquisition of individual strategically important properties, securing occupancy rights, supporting non-profit organizations, and providing suitable land.

The instruments are not directly comparable. Acquiring an existing building can secure tenancies in the short term. New construction creates additional living space but takes time. Occupancy rights can improve access for certain households without the public sector having to become the owner.

Funding commitments should not be equated with completed apartments. In Berlin, a total of 5,175 subsidized apartments were approved in 2025. Between 2015 and the end of 2025, a total of 15,848 subsidized apartments were completed under the corresponding new construction fund. The difference between approval and completion illustrates the time dimension of housing policy programs.

A meaningful comparison must therefore take several factors into account: the use of public funds, the number of households reached, the duration of the commitment, the speed of the effect, and the risk assumed.

The cheapest measure per apartment is not necessarily the best. A short-term, inexpensive commitment may be less valuable than a permanently secured apartment. Conversely, a high homeownership rate is not an end in itself if more households in need can be reached through other means.

Political credibility arises from verifiable commitments

The Berlin debate has a unique democratic history. In the referendum on September 26, 2021, 57.6 percent of voters supported the corresponding initiative to socialize large housing stocks. This sent a clear political signal. However, it did not replace the need for concrete legislation or an economic analysis of an implementation model.

Especially with a project like this, political communication must distinguish between goal, expectation, and guarantee. A goal might be to reduce rents in the long term. An expectation might be that the increase will be lower than with private management. A guarantee, on the other hand, presupposes that the promised result is actually secured under the defined conditions.

These differences are not merely a linguistic detail. They determine whether people can correctly assess the impact on their own life plans.

For many households, affordable housing is not an abstract question of distribution, but a prerequisite for professional and family stability. Accordingly, expectations are high for political proposals that promise fundamental change.

A credible presentation would therefore have to disclose for which properties and households relief is planned, what rent development is being targeted, and what cost assumptions underlie it.

Equally important is the statement about what happens under less favorable conditions. Who bears unexpected additional costs? Are investments postponed? Does the public budget intervene? Could rents rise more sharply than originally anticipated?

The more concretely these questions are answered, the less the debate depends on exaggerated promises and subsequent relativizations.

The decisive test is a complete business plan

A sound decision on socialization requires a calculation that goes beyond the purchase price or compensation amount.

The first step is a sufficiently accurate inventory. This includes living space, rental agreements, vacancies, building technology, energy efficiency, and foreseeable repairs. Without this information, it remains unclear what income and expenses can actually be expected.

Building on this, financing must be linked to management. A low interest rate is of little use if the need for renovation is simultaneously underestimated. Conversely, a well-maintained portfolio can offer more social flexibility than an outwardly inexpensive acquisition with high subsequent costs.

The business plan must also differentiate between one-off and ongoing risks. Legal and transfer costs carry different weight than ongoing interest or recurring maintenance.

A realistic approach to cost savings is particularly important. Efficiency gains should not be planned simply because they are politically desirable. They must be organizationally achievable and must not compromise service quality.

Finally, the model requires different scenarios. A basic calculation can represent favorable or average conditions. Additionally, it must be possible to see how higher construction costs, less favorable interest rates, or greater repair needs would affect the model.

Only such a comprehensive calculation allows for a central evaluation: How much social relief is actually achieved, how permanent is it, and what risk does the general public assume for it?

Affordable housing requires a strategy that goes beyond the question of ownership

The statement that rents can still rise even after socialization is not economically surprising. What is surprising is how often the public debate treats ownership structures and cost developments as if one could be completely negated by changing the other.

A public or non-profit owner can be bound by different objectives than a profit-oriented company. They can strengthen social protections, use surpluses differently, and secure long-term commitments. These are relevant possibilities.

Their limitations lie in the actual costs and the lack of additional housing. Buildings must be maintained, investments financed, and apartments provided for new households. These tasks exist regardless of who owns the buildings.

The economically convincing perspective is therefore neither a blanket promise of expropriation nor the assertion that the market will adequately solve the housing shortage without public intervention. A sensible approach is a combination of reliable tenant protection, professional property management, additional housing construction, and targeted support for low-income households.

Nationalization can be an instrument within such a strategy. Whether it is the appropriate one depends on compensation, financing, administrative quality, and its actual relief effect.

Berlin's housing policy should therefore not be judged by how far-reaching a change in ownership sounds. What matters is whether more people can live permanently in adequate housing without the financing being based on unrealistic assumptions or shifted burdens. The social quality of a housing reform is not demonstrated by promises alone, but by the long-term sustainability of its calculations.