More homes give renters more leverage.

Across citywide reforms and individual projects, more housing means lower rents than continued scarcity. Sometimes rents fall. In fast-growing places, they may simply rise less.

What this does not mean: No serious evidence says every project lowers every rent immediately. Magnitudes vary, and booming demand can still push nominal rents upward while new supply restrains that increase.

Figures from the papers

Inspect the published evidence directly

Study chart · redrawn

Figure 3 · Synthetic and actual rental price indexes

The actual and synthetic rent indexes track closely before 2016 and separate after the reform.

REDRAWN FROM STUDY DATAFigure 3 · Synthetic and actual rental price indexes

Figure 3 · Synthetic and actual rental price indexes. Series recovered from the vector paths in published Figure 3 and checked against its axes and reported 2022 gap.
Year	Actual Auckland	No-reform comparison
2000	-0.632	-0.621
2001	-0.611	-0.61
2002	-0.531	-0.57
2003	-0.456	-0.517
2004	-0.435	-0.463
2005	-0.426	-0.426
2006	-0.406	-0.372
2007	-0.353	-0.316
2008	-0.314	-0.275
2009	-0.311	-0.27
2010	-0.276	-0.236
2011	-0.225	-0.211
2012	-0.187	-0.182
2013	-0.151	-0.173
2014	-0.108	-0.145
2015	-0.046	-0.094
2016	0	0
2017	0.04	0.078
2018	0.068	0.151
2019	0.094	0.246
2020	0.117	0.307
2021	0.145	0.394
2022	0.167	0.47

Study chart · redrawn

Figure 2 · Rent event studies

Both comparison strategies turn negative after treatment; the vertical bars show uncertainty.

REDRAWN FROM STUDY DATAFigure 2 · Rent event studies

Figure 2 · Rent event studies. Values digitized from Figure 2 in the archived publication; minor reading error is possible.
Years relative to opening	Near–far comparison	Near–near comparison
−3	0.01	0.02
−2	0	-0.01
−1	0	0
0	-0.05	-0.045
+1	-0.065	-0.06
+2	-0.055	-0.05
+3	-0.05	-0.075

Study chart · redrawn

Figure 3 · Rents before and after the completion year

The completion event study shows little pre-trend and a growing negative rent effect afterward.

REDRAWN FROM STUDY DATAFigure 3 · Rents before and after the completion year

Figure 3 · Rents before and after the completion year. Values digitized from Figure 3; the one-year estimate is checked against the reported −1.6% result in the archived publication; minor reading error is possible.
Years relative to completion	Nearby existing rentals
−5	0.1
−4	0.15
−3	0.05
−2	0.1
−1	0
0	-0.25
+1	-0.55
+2	-0.9
+3	-1.25
+4	-1.55
+5	-1.8

Study chart · redrawn

Figure 3 · Impact of new housing supply on the distribution of rents

Every rent-quality decile has a negative estimate; the vertical bars show 95% confidence intervals.

REDRAWN FROM STUDY DATAFigure 3 · Impact of new housing supply on the distribution of rents

Figure 3 · Impact of new housing supply on the distribution of rents. Values digitized from Figure 3 and centered on the authors’ reported average elasticity of −0.19 in the archived publication; minor reading error is possible.
Rent-quality decile	Quality-adjusted posted rent
Lowest rent	-0.15
2	-0.16
3	-0.17
4	-0.18
5	-0.19
6	-0.2
7	-0.21
8	-0.22
Highest rent	-0.24

Evidence stack

Studies behind this conclusion

Greenaway-McGrevy & So, 2026Peer reviewed

Can Zoning Reform Reduce Housing Costs? Evidence from Auckland

After Auckland's construction boom, quality-adjusted rents were substantially below the estimated path without reform.

Preferred estimate: the no-reform rent path was about 28% higher after six years

Keep in mind: This is one treated city, and the magnitude varies across specifications.

Study details →

Li, 2022Peer reviewed

Do New Housing Units in Your Backyard Raise Your Rents?

Completed high-rises lowered nearby rents and sale prices even while attracting restaurants, suggesting the local supply effect outweighed the amenity effect.

A 10% local stock increase lowered nearby rents by about 1%

Keep in mind: The rent data omit many small buildings, and the result is hyperlocal.

Study details →

Asquith, Mast & Reed, 2023Peer reviewed

Local Effects of Large New Apartment Buildings in Low-Income Areas

Large market-rate buildings lowered nearby listed rents in low-income neighborhoods and drew movers from other low-income areas.

Nearby listed rents fell 5–7% relative to trend

Keep in mind: The main sample contains 96 buildings, and Zillow underrepresents cheaper rentals.

Study details →

Mense, 2025Peer reviewed

The Impact of New Housing Supply on the Distribution of Rents

New supply reduced rents across the quality distribution and expanded the availability of second-hand homes, including in high-demand markets.

A 1% increase in annual new supply lowered average rents by 0.19%

Keep in mind: The setting is Germany and the outcome is posted rather than contract rent.

Study details →

From evidence to policy

Reforms connected to this claim

01Make room for apartments, shops, and neighborsStop reserving most well-located land for the most expensive kind of home. Let more people live near jobs, schools, shops, and opportunity.

All evidence claims Search the research library