Koppers Holdings Inc.
US ˙ NYSE ˙ US50060P1066

SecurityKOP / Koppers Holdings Inc.
InstitutionBoston Partners
Latest Disclosed Ownership16,578 shares
Latest Disclosed Value $ 641,240
Boston Partners reports 24.92% decrease in ownership of KOP / Koppers Holdings Inc.

On May 11, 2026 - Boston Partners filed a 13F-HR form disclosing ownership of 16,578 shares of Koppers Holdings Inc. (US:KOP) valued at $641,237 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 22,080 shares of Koppers Holdings Inc.. This represents a change in shares of -24.92% during the quarter. The current value of the position is $714,346 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)
2026-05-11 2026-03-31 13F KOPPERS HOLDINGS COM 50060P106 16,578 -5,502 -24.92 641 7.37 0.0003
2026-02-13 2025-12-31 13F KOPPERS HOLDINGS COM 50060P106 22,080 937 4.43 598 0.84 0.0006
2025-11-13 2025-09-30 13F KOPPERS HOLDINGS COM 50060P106 21,143 4,534 27.30 592 11.07 0.0006
2025-08-12 2025-06-30 13F/A-1 KOPPERS HOLDINGS COM 50060P106 16,609 26 0.16 534 14.87 0.0006
2025-08-07 2025-06-30 13F KOPPERS HOLDINGS COM 50060P106 16,609 26 534 0.0002
2025-05-13 2025-03-31 13F KOPPERS HOLDINGS COM 50060P106 16,583 9,079 120.99 464 90.95 0.0006
2025-02-11 2024-12-31 13F KOPPERS HOLDINGS COM 50060P106 7,504 7,504 243 0.0003
2015-11-10 2015-09-30 13F KOPPERS HOLDINGS COM 50060P106 0 -226,486 -100.00 0 -100.00
2015-08-10 2015-06-30 13F KOPPERS HOLDINGS COM 50060P106 226,486 49,030 27.63 5,599 60.34 0.0080
2015-05-05 2015-03-31 13F KOPPERS HOLDINGS COM 50060P106 177,456 -44,445 -20.03 3,492 -39.43 0.0052
2015-02-09 2014-12-31 13F KOPPERS HOLDINGS COM 50060P106 221,901 38,063 20.70 5,765 -5.43 0.0087
2014-11-12 2014-09-30 13F KOPPERS HOLDINGS COM 50060P106 183,838 29,399 19.04 6,096 3.20 0.0099
2014-08-08 2014-06-30 13F KOPPERS HOLDINGS COM 50060P106 154,439 24,006 18.40 5,907 9.84 0.0099
2014-05-07 2014-03-31 13F KOPPERS HOLDINGS COM 50060P106 130,433 130,433 61.36 5,378 55.97 0.0098
2014-02-06 2013-12-31 13F KOPPERS HOLDINGS COM 50060P106 0 -80,833 -100.00 0 -100.00
2013-11-12 2013-09-30 13F KOPPERS HOLDINGS COM 50060P106 80,833 80,833 3,448 0.0083
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.