Proto Labs, Inc.
US ˙ NYSE ˙ US7437131094

SecurityPRLB / Proto Labs, Inc.
InstitutionNorthern Trust Corp
Latest Disclosed Ownership266,951 shares
Latest Disclosed Value $ 15,221,546
Northern Trust Corp reports 4.17% increase in ownership of PRLB / Proto Labs, Inc.

On May 14, 2026 - Northern Trust Corp filed a 13F-HR form disclosing ownership of 266,951 shares of Proto Labs, Inc. (US:PRLB) valued at $15,221,546 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 256,268 shares of Proto Labs, Inc.. This represents a change in shares of 4.17% during the quarter. The current value of the position is $19,933,231 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)
2026-05-14 2026-03-31 13F PROTO LABS COM 743713109 266,951 10,683 4.17 15,222 17.41 0.0004
2026-02-17 2025-12-31 13F PROTO LABS COM 743713109 256,268 -22,473 -8.06 12,965 -7.03 0.0017
2025-11-14 2025-09-30 13F PROTO LABS COM 743713109 278,741 -1,091 -0.39 13,945 24.46 0.0018
2025-08-13 2025-06-30 13F PROTO LABS COM 743713109 279,832 8,042 2.96 11,204 17.65 0.0015
2025-05-13 2025-03-31 13F PROTO LABS COM 743713109 271,790 -9,849 -3.50 9,524 -13.50 0.0014
2025-02-14 2024-12-31 13F PROTO LABS COM 743713109 281,639 9,314 3.42 11,009 37.65 0.0016
2024-11-13 2024-09-30 13F PROTO LABS COM 743713109 272,325 -10,338 -3.66 7,998 -8.40 0.0013
2024-08-14 2024-06-30 13F PROTO LABS COM 743713109 282,663 -9,702 -3.32 8,731 -16.47 0.0015
2024-05-14 2024-03-31 13F PROTO LABS COM 743713109 292,365 -6,701 -2.24 10,452 -10.29 0.0018
2024-02-13 2023-12-31 13F PROTO LABS COM 743713109 299,066 510 0.17 11,652 47.84 0.0021
2023-11-13 2023-09-30 13F PROTO LABS COM 743713109 298,556 -1,464 -0.49 7,882 -24.86 0.0015
2023-08-11 2023-06-30 13F PROTO LABS COM 743713109 300,020 -9,385 -3.03 10,489 2.26 0.0020
2023-05-15 2023-03-31 13F PROTO LABS COM 743713109 309,405 4,732 1.55 10,257 31.86 0.0020
2023-02-13 2022-12-31 13F PROTO LABS COM 743713109 304,673 1,529 0.50 7,778 -29.57 0.0016
2022-11-14 2022-09-30 13F PROTO LABS COM 743713109 303,144 -6,170 -1.99 11,043 -25.38 0.0025
2022-08-12 2022-06-30 13F PROTO LABS COM 743713109 309,314 -5,505 -1.75 14,798 -11.14 0.0032
2022-05-13 2022-03-31 13F PROTO LABS COM 743713109 314,819 -19,860 -5.93 16,653 -3.11 0.0029
2022-02-08 2021-12-31 13F PROTO LABS COM 743713109 334,679 -100,606 -23.11 17,187 -40.72 0.0028
2021-11-15 2021-09-30 13F PROTO LABS COM 743713109 435,285 88,346 25.46 28,991 -8.97 0.0051
2021-08-13 2021-06-30 13F PROTO LABS COM 743713109 346,939 -13,564 -3.76 31,849 -27.44 0.0056
2021-05-12 2021-03-31 13F PROTO LABS COM 743713109 360,503 -45,923 -11.30 43,891 -29.60 0.0082
2021-02-11 2020-12-31 13F PROTO LABS COM 743713109 406,426 -19,501 -4.58 62,345 13.03 0.0121
2020-11-16 2020-09-30 13F PROTO LABS COM 743713109 425,927 -19,992 -4.48 55,158 9.98 0.0121
2020-08-14 2020-06-30 13F PROTO LABS COM 743713109 445,919 12,801 2.96 50,152 52.10 0.0119
2020-05-14 2020-03-31 13F PROTO LABS COM 743713109 433,118 9,977 2.36 32,973 -23.27 0.0095
2020-02-14 2019-12-31 13F PROTO LABS COM 743713109 423,141 -15,951 -3.63 42,970 -4.15 0.0096
2019-11-13 2019-09-30 13F PROTO LABS COM 743713109 439,092 14,212 3.34 44,832 -9.05 0.0107
2019-08-13 2019-06-30 13F PROTO LABS COM 743713109 424,880 1,742 0.41 49,294 10.80 0.0117
2019-05-13 2019-03-31 13F PROTO LABS COM 743713109 423,138 2,620 0.62 44,489 -6.20 0.0110
2019-02-12 2018-12-31 13F PROTO LABS COM 743713109 420,518 -3,385 -0.80 47,430 -30.82 0.0133
2018-11-14 2018-09-30 13F PROTO LABS COM 743713109 423,903 15,465 3.79 68,565 41.13 0.0168
2018-09-18 2018-06-30 13F/A-1 PROTO LABS COM 743713109 408,438 27,051 7.09 48,583 8.37 0.0123
2018-08-14 2018-06-30 13F PROTO LABS COM 743713109 410,185 28,798 48,791
2018-05-09 2018-03-31 13F PROTO LABS COM 743713109 381,387 -2,329 -0.61 44,832 13.43 0.0117
2018-02-14 2017-12-31 13F PROTO LABS COM 743713109 383,716 -8,987 -2.29 39,523 25.33 0.0100
2017-11-13 2017-09-30 13F PROTO LABS COM 743713109 392,703 -10,716 -2.66 31,534 16.23 0.0082
2017-08-11 2017-06-30 13F PROTO LABS COM 743713109 403,419 15,600 4.02 27,130 36.90 0.0076
2017-05-12 2017-03-31 13F PROTO LABS COM 743713109 387,819 4,149 1.08 19,817 0.58 0.0057
2017-02-13 2016-12-31 13F PROTO LABS COM 743713109 383,670 -159,465 -29.36 19,702 -39.45 0.0060
2016-11-09 2016-09-30 13F PROTO LABS COM 743713109 543,135 18,181 3.46 32,539 7.69 0.0101
2016-08-12 2016-06-30 13F PROTO LABS COM 743713109 524,954 10,856 2.11 30,216 -20.60 0.0098
2016-08-19 2016-03-31 13F/A-1 PROTO LABS COM 743713109 514,098 8,687 1.72 38,056 18.22 0.0126
2016-05-13 2016-03-31 13F Proto Labs COMM 743713109 514,097 39,631
2016-02-12 2015-12-31 13F Proto Labs COMM 743713109 505,411 5,012 1.00 32,190 -3.99 0.0107
2015-11-12 2015-09-30 13F Proto Labs COMM 743713109 500,399 500,399 0.00 33,527 0.0112
2015-08-13 2015-06-30 13F Proto Labs COMM 743713109 0 -463,562 -100.00 0 -100.00
2015-05-14 2015-03-31 13F Proto Labs COMM 743713109 463,562 1,357 0.29 32,449 4.53 0.0098
2015-02-12 2014-12-31 13F Proto Labs COM 743713109 462,205 34,788 8.14 31,042 5.26 0.0094
2014-11-13 2014-09-30 13F Proto Labs COMM 743713109 427,417 146,188 51.98 29,492 28.01 0.0093
2014-08-14 2014-06-30 13F PROTO LABS com 743713109 281,229 -109,948 -28.11 23,039 -12.97 0.0072
2014-05-14 2014-03-31 13F PROTO LABS COMM 743713109 391,177 94,468 31.84 26,471 25.34 0.0083
2014-02-21 2013-12-31 13F/A-1 PROTO LABS COM 743713109 296,709 -13,381 -4.32 21,119 -10.85 0.0068
2014-02-12 2013-12-31 13F PROTO LABS COM 743713109 296,709 21,119
2013-11-13 2013-09-30 13F PROTO LABS COM 743713109 310,090 112,889 57.25 23,689 84.90 0.0083
2013-08-09 2013-06-30 13F PROTO LABS COM 743713109 197,201 197,201 12,812 0.0046
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.