Armstrong World Industries, Inc.
US ˙ NYSE ˙ US04247X1028

SecurityAWI / Armstrong World Industries, Inc.
InstitutionDimensional Fund Advisors Lp
Latest Disclosed Ownership842,952 shares
Latest Disclosed Value $ 138,903,742
Dimensional Fund Advisors Lp reports 1.75% decrease in ownership of AWI / Armstrong World Industries, Inc.

On May 7, 2026 - Dimensional Fund Advisors Lp filed a 13F-HR form disclosing ownership of 842,952 shares of Armstrong World Industries, Inc. (US:AWI) valued at $138,918,490 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 858,005 shares of Armstrong World Industries, Inc.. This represents a change in shares of -1.75% during the quarter. The current value of the position is $130,784,003 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-07 2026-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 842,952 -15,053 -1.75 138,904 -15.29 0.0062
2026-02-12 2025-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 858,005 -2,794 -0.32 163,968 -2.81 0.0344
2025-11-12 2025-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 860,799 2,799 0.33 168,716 21.05 0.0362
2025-08-12 2025-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 858,000 -43,636 -4.84 139,378 9.74 0.0323
2025-05-13 2025-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 901,636 -61,295 -6.37 127,014 -6.67 0.0316
2025-02-13 2024-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 962,931 -41,977 -4.18 136,095 3.04 0.0327
2024-11-07 2024-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,004,908 -29,486 -2.85 132,073 12.75 0.0320
2024-08-09 2024-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,034,394 -33,668 -3.15 117,134 -11.71 0.0306
2024-05-10 2024-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,068,062 18,299 1.74 132,675 28.54 0.0359
2024-02-07 2023-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,049,763 32,133 3.16 103,215 40.86 0.0301
2023-11-09 2023-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,017,630 1,627 0.16 73,274 -1.83 0.0240
2023-08-09 2023-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,016,003 59,074 6.17 74,636 9.49 0.0238
2023-05-12 2023-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 956,929 4,686 0.49 68,168 104,772.31 0.0230
2023-02-09 2022-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 952,243 3,241 0.34 65 -99.91 0.0193
2022-11-10 2022-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 949,002 -5,448 -0.57 75,190 5.10 0.0289
2022-08-12 2022-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 954,450 -5,790 -0.60 71,544 -17.23 0.0257
2022-05-13 2022-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 960,240 -15,019 -1.54 86,438 -23.67 0.0266
2022-02-09 2021-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 975,259 -21,308 -2.14 113,245 19.02 0.0342
2021-11-12 2021-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 996,567 4,493 0.45 95,148 -10.58 0.0306
2021-08-12 2021-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 992,074 -20,000 -1.98 106,411 16.70 0.0337
2021-05-14 2021-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,012,074 -2,246 -0.22 91,182 20.84 0.0302
2021-03-08 2020-12-31 13F/A-2 ARMSTRONG WORLD INDS COM 04247X102 1,014,320 -4,988 -0.49 75,455 7.57 0.0272
2021-02-11 2020-12-31 13F ARMSTRONG WORLD INDS COM 04247X102 1,014,320 -4,988 75,455 27,250.3353
2020-11-12 2020-09-30 13F ARMSTRONG WORLD INDS COM 04247X102 1,019,308 -54,323 -5.06 70,142 -16.19 0.0297
2020-08-13 2020-06-30 13F ARMSTRONG WORLD INDS COM 04247X102 1,073,631 -69,213 -6.06 83,690 -7.80 0.0368
2020-05-14 2020-03-31 13F ARMSTRONG WORLD INDS COM 04247X102 1,142,844 -37,857 -3.21 90,771 -18.19 0.0473
2020-02-14 2019-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,180,701 -77,272 -6.14 110,950 -8.79 0.0404
2019-11-12 2019-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,257,973 -6,957 -0.55 121,645 -1.06 0.0473
2019-08-13 2019-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,264,930 -31,429 -2.42 122,953 19.43 0.0477
2019-08-12 2019-03-31 13F/A-2 ARMSTRONG WORLD INDS INC COM 04247X102 1,296,359 -5,525 -0.42 102,954 35.86 0.0410
2019-05-10 2019-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,296,359 -5,525 102,954
2019-02-26 2018-12-31 13F/A-1 ARMSTRONG WORLD INDS INC COM 04247X102 1,301,884 22,959 1.80 75,782 -14.87 0.0343
2019-02-13 2018-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,301,884 22,959 75,782
2018-11-13 2018-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,278,925 8,451 0.67 89,014 10.86 0.0339
2018-08-10 2018-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,270,474 6,203 0.49 80,293 12.81 0.0320
2018-05-11 2018-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,264,271 9,990 0.80 71,178 -6.28 0.0297
2018-02-12 2017-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,254,281 7,187 0.58 75,946 18.83 0.0315
2017-11-13 2017-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,247,094 22,833 1.87 63,914 13.49 0.0279
2017-08-11 2017-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,224,261 26,548 2.22 56,315 2.11 0.0260
2017-05-12 2017-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,197,713 1,550 0.13 55,153 10.30 0.0264
2017-02-09 2016-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,196,163 1,950 0.16 50,001 1.33 0.0250
2016-11-10 2016-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,194,213 -2,310 -0.19 49,343 5.34 0.0267
2016-08-09 2016-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,196,523 75,149 6.70 46,842 -13.64 0.0270
2016-05-13 2016-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,121,374 12,009 1.08 54,240 6.91 0.0325
2016-02-10 2015-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,109,365 64,633 6.19 50,732 1.72 0.0316
2015-11-13 2015-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,044,732 24,785 2.43 49,874 -8.22 0.0327
2015-08-14 2015-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 1,019,947 135,273 15.29 54,343 6.89 0.0333
2015-05-14 2015-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 884,674 230,504 35.24 50,841 52.03 0.0321
2015-02-06 2014-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 654,170 279,642 74.67 33,441 59.43 0.0220
2014-11-13 2014-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 374,528 61,262 19.56 20,975 16.59 0.0149
2014-08-08 2014-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 313,266 105,035 50.44 17,991 62.27 0.0125
2014-05-14 2014-03-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 208,231 612 0.29 11,087 -7.30 0.0083
2014-02-12 2013-12-31 13F ARMSTRONG WORLD INDS INC COM 04247X102 207,619 -34,215 -14.15 11,960 -10.01 0.0093
2013-11-13 2013-09-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 241,834 -21,100 -8.02 13,291 5.77 0.0115
2013-08-15 2013-06-30 13F ARMSTRONG WORLD INDS INC COM 04247X102 262,934 262,934 12,566 0.0118
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.