> Rent control for existing properties raises market rents by encouraging existing tenants to stay even if their apartment is bigger than they need anymore and they might otherwise move to a smaller one or e.g. retire to Florida or Arizona, thereby keeping those units off the market and requiring the remaining demand to be satisfied by fewer units.

Rent would only be cheaper in "rent-controlled" properties during periods of extreme growth in market rents. The primary issue in such cases is not "mis-matched" tenants (if anything, reducing churn should increase effective supply). While it would provide less incentive for retirees to move out of the city , it also limits the degree to which the impoverished are forced to leave the city. Once the period of extreme growth passes, all rents will stabilize back at the market price.

So yes, this can lead to slightly higher market rents for new tenants during periods of extreme growth, but it does this because fewer people are forced out of the city.

> And the prospect of rent control at any point in the future lowers the net present value of those investments by the corresponding amount, causing reduced investment in building new housing.

You think you can predict accurately which cities will have rent-control laws 15 years from now? While I can see how current or near-term rent control can affect a properties value, the incredibly marginal effects of this 15 years out is complete washed out by the much larger unknowns that affect the value of the property 15 years from now. One could has plausibly even argue that seeing a law like Oregon's being passed reduces the chance of seeing more draconian rent control laws introduced, which should INCREASE the attractiveness of investing in rentals in Oregon.

> Worse, if the old buildings have rent control and the new ones don't, the tenants will prefer a rent controlled apartment, driving rents up in the old buildings and down in the new buildings (because, unlike investors, tenants do specifically need housing in that city so the relative difference matters), which both increases rents on existing buildings and reducing the incentive to build new buildings.

>Worse, if the old buildings have rent control and the new ones don't, the tenants will prefer a rent controlled apartment, driving rents up in the old buildings and down in the new buildings (because, unlike investors, tenants do specifically need housing in that city so the relative difference matters), which both increases rents on existing buildings and reducing the incentive to build new buildings.

This is completely wrong and confused.

Somehow you have created a situation where in your mind where:

1) the tenants expects to pay less rent (over the next X years) on OLD buildings

somehow implies

2) the investor expects to be paid less rent (over the next X years)on NEW buildings.

Obviously, one of those expectations must be wrong which means your argument is invalid.

If you do see lower initial rents on newer buildings, you only see them offered to the degree that landlords expect to make up the difference in the following years.

If you do see higher initial rents on older buildings, you only see them paid to the degree that renters expect to make up the difference in the following years.