The value of an asset is determined by the expected return to investors (i.e. rent). If you reduce expected returns by limiting rent, your asset (the apartment

The value of an asset is determined by the expected return to investors (i.e. rent). If you reduce expected returns by limiting rent, your asset (the apartment building) is suddenly worth less. But the typical rent control regulation only covers older building. If you are a developer of new apartments, you can benefit here. Your competition is under rent control, so their current tenants have a strong incentive to remain in older buildings. This reduces supply, and your new apartment building can raise prices.