Dimensional Fund Advisors’s Iron Mountain IRM Stock Holding History

Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake
Trade Value Portfolio Weight Portfolio Position
2026
Q1
$465M Buy
4,552,286
+122,927
+3% +$12.2M 0.1% 176
2025
Q4
$367M Buy
4,429,359
+81,320
+2% +$7.61M 0.08% 251
2025
Q3
$443M Buy
4,348,039
+55,273
+1% +$5.32M 0.1% 175
2025
Q2
$440M Buy
4,292,766
+36,349
+0.9% +$3.43M 0.1% 155
2025
Q1
$366M Buy
4,256,417
+37,154
+0.9% +$3.58M 0.09% 194
2024
Q4
$443M Buy
4,219,263
+15,097
+0.4% +$1.77M 0.11% 138
2024
Q3
$500M Sell
4,204,166
-81,902
-2% -$8.76M 0.12% 120
2024
Q2
$384M Sell
4,286,068
-525
-0% -$42.5K 0.1% 156
2024
Q1
$344M Sell
4,286,593
-1,806
-0% -$131K 0.09% 183
2023
Q4
$300M Sell
4,288,399
-15,517
-0.4% -$973K 0.09% 206
2023
Q3
$256M Buy
4,303,916
+32,452
+0.8% +$1.98M 0.08% 223
2023
Q2
$243M Buy
4,271,464
+52,274
+1% +$2.86M 0.08% 252
2023
Q1
$223M Buy
4,219,190
+116,057
+3% +$6.08M 0.08% 270
2022
Q4
$205K Buy
4,103,133
+54,106
+1% +$2.73M 0.06% 311
2022
Q3
$178M Sell
4,049,027
-9,556
-0.2% -$483K 0.07% 334
2022
Q2
$198M Sell
4,058,583
-6,850
-0.2% -$360K 0.07% 305
2022
Q1
$225M Sell
4,065,433
-84,543
-2% -$4.03M 0.07% 310
2021
Q4
$217M Sell
4,149,976
-72,078
-2% -$3.41M 0.07% 329
2021
Q3
$183M Sell
4,222,054
-44,123
-1% -$1.99M 0.06% 397
2021
Q2
$181M Buy
4,266,177
+14,291
+0.3% +$599K 0.06% 406
2021
Q1
$157M Sell
4,251,886
-15,688
-0.4% -$525K 0.05% 476
2020
Q4
$126M Sell
4,267,574
-92,296
-2% -$2.56M 0.05% 559
2020
Q3
$117M Sell
4,359,870
-41,696
-0.9% -$1.19M 0.05% 464
2020
Q2
$115M Buy
4,401,566
+16,081
+0.4% +$406K 0.05% 448
2020
Q1
$104M Sell
4,385,485
-31,588
-0.7% -$956K 0.05% 387
2019
Q4
$141M Buy
4,417,073
+38,156
+0.9% +$1.25M 0.05% 463
2019
Q3
$142M Buy
4,378,917
+171,346
+4% +$5.38M 0.06% 417
2019
Q2
$132M Buy
4,207,571
+40,947
+1% +$1.34M 0.05% 473
2019
Q1
$148M Buy
4,166,624
+38,825
+0.9% +$1.37M 0.06% 369
2018
Q4
$134M Buy
4,127,799
+45,950
+1% +$1.51M 0.06% 335
2018
Q3
$141M Buy
4,081,849
+58,036
+1% +$2.07M 0.05% 434
2018
Q2
$141M Buy
4,023,813
+99,620
+3% +$3.36M 0.06% 426
2018
Q1
$129M Buy
3,924,193
+173,605
+5% +$5.85M 0.05% 442
2017
Q4
$142M Buy
3,750,588
+139,758
+4% +$5.55M 0.06% 394
2017
Q3
$140M Buy
3,610,830
+80,395
+2% +$3M 0.06% 371
2017
Q2
$121M Buy
3,530,435
+124,704
+4% +$4.36M 0.06% 418
2017
Q1
$121M Buy
3,405,731
+94,324
+3% +$3.34M 0.06% 418
2016
Q4
$108M Buy
3,311,407
+275,336
+9% +$9.15M 0.05% 456
2016
Q3
$114M Buy
3,036,071
+404,230
+15% +$15.6M 0.06% 383
2016
Q2
$105M Buy
2,631,841
+29,225
+1% +$1.06M 0.06% 369
2016
Q1
$88.3M Buy
2,602,616
+126,417
+5% +$3.63M 0.05% 442
2015
Q4
$66.9M Buy
2,476,199
+670,436
+37% +$19.7M 0.04% 609
2015
Q3
$56M Buy
1,805,763
+637,488
+55% +$19M 0.04% 707
2015
Q2
$36.2M Sell
1,168,275
-16,405
-1% -$575K 0.02% 1223
2015
Q1
$43.2M Buy
1,184,680
+379,921
+47% +$14.7M 0.03% 988
2014
Q4
$31.1M Buy
804,759
+125,266
+18% +$4.56M 0.02% 1269
2014
Q3
$22.2M Sell
679,493
-155,832
-19% -$5.05M 0.02% 1524
2014
Q2
$27.4M Buy
835,325
+264,957
+46% +$7.19M 0.02% 1313
2014
Q1
$14.5M Buy
570,368
+206,115
+57% +$5.27M 0.01% 1878
2013
Q4
$10.2M Buy
364,253
+6,183
+2% +$158K 0.01% 2150
2013
Q3
$8.94M Buy
358,070
+7,574
+2% +$192K 0.01% 2195
2013
Q2
$8.62M Buy
+350,496
New +$11.3M 0.01% 2134

Other funds holding IRM

Dimensional Fund Advisors's IRM Position: Q1 2026 in Review

Dimensional Fund Advisors increased its Iron Mountain (IRM) stake by 2.8% in Q1 2026, buying an estimated $12.2M and bringing the position to 4,552,286 shares worth $465M. The position accounts for 0.1% of the portfolio, ranked #176.

Dimensional Fund Advisors first reported a position in IRM in Q2 2013 and has held it in 52 quarters since. The position peaked at $500M in Q3 2024. 1,082 funds tracked by Wall St. Rank hold IRM as of Q1 2026.

  • Dimensional Fund Advisors held 4,552,286 shares of Iron Mountain worth $465M as of Q1 2026.
  • Dimensional Fund Advisors bought 122,927 Iron Mountain shares in Q1 2026, an estimated $12.2M.
  • Iron Mountain made up 0.1% of Dimensional Fund Advisors's portfolio in Q1 2026, its #176 holding.
  • Dimensional Fund Advisors first reported a position in Iron Mountain in Q2 2013 and has held it in 52 quarters since.
  • Dimensional Fund Advisors's Iron Mountain position peaked at $500M in Q3 2024.
  • 1,082 funds tracked by Wall St. Rank held Iron Mountain as of Q1 2026.

Based on Dimensional Fund Advisors's 13F filing for Q1 2026, filed 7 May 2026.