I analyzed 10,925 duplex, triplex and fourplex sales to test whether St. Paul's rent control hurt values, and the results surprised me.

This is a long post, but I think the methodology matters more than the headline, so I'm showing my work. Tell me what I got wrong.

BACKGROUND

St. Paul passed rent stabilization by ballot initiative in November 2021, and the ordinance took effect May 1 2022 with a 3% annual cap, no vacancy decontrol initially, applied to essentially all rental housing. It was amended effective January 2023 and again on June 13 2025.

Minneapolis voters approved a separate question in November 2021 authorizing their city council to enact rent control, but the council never did, voting a draft down 5-4 in June 2023 with a mayoral veto threatened. There's no cap in Minneapolis, then or now.

That gives you a usable natural experiment, because you have two adjacent cities in one metro with the same interest rate environment, the same labor market and the same migration patterns, and only one of them got a rent cap.

THE DATA

Every closed 2-4 unit residential sale in both cities from December 27 2012 through September 4 2026, out of NorthstarMLS. I used an identical date window for both cities and checked this specifically, because if one pull covered a different era the whole comparison would be worthless.

That came to 4,065 sales in St. Paul and 6,860 in Minneapolis, for 10,925 total.

WHY YOU CAN'T JUST LOOK AT ST. PAUL

St. Paul price per door growth went from about 11% annually between 2013 and 2021 to about 2% annually from 2022 to 2025, which looks like a smoking gun until you remember that mortgage rates went from 3% to over 7% starting in early 2022. Nearly every US market flattened that year, and a single-city before-and-after cannot separate the ordinance from the rate shock. That's the entire reason for the Minneapolis comparison.

RESULTS

Median price per unit, St. Paul as a percentage of Minneapolis:

2013: 74%

2015: 70%

2017: 69%

2019: 72%

2021: 76%

2022: 81%

2023: 83%

2024: 81%

2025: 82%

2026: 87%

St. Paul closed the gap after the cap took effect.

Running it as a regression controlling for finished square feet, unit count, year built, lot size and ZIP code, with city-by-year interaction terms, St. Paul averaged 20.4% below Minneapolis from 2013 to 2021 and 13.0% below from 2022 to 2026, a shift of 7.4 points in St. Paul's favor. That's on n = 10,894 with an R-squared of 0.73.

PARALLEL TRENDS

This is the assumption everything rests on, so I tested it. The pre-2022 trend in the gap between cities is +0.62 points per year with a 95% confidence interval of -0.21 to +1.45, which is not significantly different from zero. The two cities were tracking each other before the ordinance, and if St. Paul had already been closing the gap for years then none of this would mean anything.

VOLUME

St. Paul 2-4 unit sales fell roughly 25% from the 2021 peak. Indexed to each city's own 2013-2019 baseline, St. Paul ran 153 in 2021 against Minneapolis at 145, then 116 against 125 in 2022, 104 against 93 in 2023, 91 against 91 in 2024, and 87 against 92 in 2025. Both cities fell together, and there's no St. Paul-specific volume collapse.

LIQUIDITY

Median days on market from 2021 to 2025-26 went from 15 to 33 in St. Paul and 14 to 31 in Minneapolis, and sale-to-original-list slipped in both cities in 2025-26.

BY UNIT COUNT

St. Paul as a share of Minneapolis price per door, before and after: duplexes went from 75.4% to 80.8%, triplexes from 71.7% to 75.0%, and fourplexes from 81.7% to 87.5%. All three moved the same direction independently.

WHAT THIS DOES NOT SHOW

1. This is 2-4 unit only. These are largely owner-occupied or small-landlord properties financed residentially, and institutional apartment buildings are a completely different market with different underwriting and different sensitivity to a rent cap. I have nothing to say about those.

2. New construction did get hit. St. Paul permits reportedly fell about 48% after the 2021 vote, which is a big part of why Minneapolis backed off, but that's about buildings that don't exist yet. Existing duplexes holding value and developers not breaking ground are separate outcomes and both can be true at the same time.

3. A 3% cap may not bind on this property type. Plenty of small landlords in century-old St. Paul duplexes were already below market and raising under 3%, and a limit you weren't going to hit costs you nothing.

4. Closing a gap is not proof of causation. St. Paul started 20% cheaper, and cheaper markets attract buyers for their own reasons. Difference-in-differences rules out shocks common to both cities, but it doesn't rule out St. Paul having independent reasons to catch up.

5. Minneapolis is not a perfect control, since their 2021 ballot question passed too. Some of the apparent non-effect could be both cities pricing in rent control risk with only one of them actually getting the law.

6. This is sale prices only, so it says nothing about rents, NOI, cap rates or realized owner returns. It's entirely possible that values held while returns compressed.

I went into this expecting to find that St. Paul got hammered, and it didn't, at least not in this property class. Poke holes in it, because I'd rather be corrected than confidently wrong.