Mesa Laboratories, Inc.
US ˙ NasdaqGS ˙ US59064R1095

SecurityMLAB / Mesa Laboratories, Inc.
InstitutionCitigroup Inc
Latest Disclosed Ownership372 shares
Latest Disclosed Value $ 32,892
Citigroup Inc reports 64.60% increase in ownership of MLAB / Mesa Laboratories, Inc.

On May 11, 2026 - Citigroup Inc filed a 13F-HR form disclosing ownership of 372 shares of Mesa Laboratories, Inc. (US:MLAB) valued at $32,892 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 226 shares of Mesa Laboratories, Inc.. This represents a change in shares of 64.60% during the quarter. The current value of the position is $38,829 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 MESA LABS COM 59064R109 372 146 64.60 33 88.24 0.0000
2026-02-13 2025-12-31 13F MESA LABS COM 59064R109 226 -238 -51.29 18 -45.16 0.0000
2025-11-10 2025-09-30 13F MESA LABS COM 59064R109 464 -5,145 -91.73 31 -94.13 0.0000
2025-08-11 2025-06-30 13F MESA LABS COM 59064R109 5,609 -3,250 -36.69 528 -49.76 0.0003
2025-05-12 2025-03-31 13F MESA LABS COM 59064R109 8,859 1,028 13.13 1,051 1.84 0.0005
2025-02-12 2024-12-31 13F MESA LABS COM 59064R109 7,831 418 5.64 1,033 7.28 0.0006
2024-11-12 2024-09-30 13F MESA LABS COM 59064R109 7,413 3,043 69.63 963 153.83 0.0006
2024-08-12 2024-06-30 13F MESA LABS COM 59064R109 4,370 764 21.19 379 -4.05 0.0002
2024-05-10 2024-03-31 13F MESA LABS COM 59064R109 3,606 285 8.58 396 13.83 0.0003
2024-02-09 2023-12-31 13F MESA LABS COM 59064R109 3,321 862 35.05 348 34.50 0.0002
2023-12-06 2023-09-30 13F/A-1 MESA LABS COM 59064R109 2,459 -1,598 -39.39 258 -50.48 0.0002
2023-11-09 2023-09-30 13F MESA LABS COM 59064R109 2,459 -1,598 258 0.0001
2023-08-10 2023-06-30 13F MESA LABS COM 59064R109 4,057 1,441 55.08 521 14.00 0.0003
2023-05-11 2023-03-31 13F MESA LABS COM 59064R109 2,616 -691 -20.90 457 -16.76 0.0003
2023-02-09 2022-12-31 13F MESA LABS COM 59064R109 3,307 578 21.18 550 42.97 0.0004
2022-11-10 2022-09-30 13F MESA LABS COM 59064R109 2,729 87 3.29 384 -28.76 0.0003
2022-08-10 2022-06-30 13F MESA LABS COM 59064R109 2,642 -2,357 -47.15 539 -57.73 0.0004
2022-05-12 2022-03-31 13F MESA LABS COM 59064R109 4,999 427 9.34 1,275 -14.94 0.0008
2022-02-10 2021-12-31 13F MESA LABS COM 59064R109 4,572 1,318 40.50 1,499 52.34 0.0008
2021-11-10 2021-09-30 13F MESA LABS COM 59064R109 3,254 -566 -14.82 984 -4.93 0.0006
2021-08-10 2021-06-30 13F MESA LABS COM 59064R109 3,820 1,645 75.63 1,035 95.28 0.0006
2021-05-13 2021-03-31 13F MESA LABS COM 59064R109 2,175 -182 -7.72 530 -21.60 0.0003
2021-02-11 2020-12-31 13F MESA LABS COM 59064R109 2,357 35 1.51 676 14.19 0.0004
2020-11-12 2020-09-30 13F MESA LABS COM 59064R109 2,322 -2,887 -55.42 592 -47.61 0.0004
2020-08-12 2020-06-30 13F MESA LABS COM 59064R109 5,209 3,480 201.27 1,130 189.00 0.0009
2020-05-12 2020-03-31 13F MESA LABS COM 59064R109 1,729 -3,144 -64.52 391 -67.82 0.0004
2020-02-12 2019-12-31 13F MESA LABS COM 59064R109 4,873 1,806 58.88 1,215 66.67 0.0009
2019-11-08 2019-09-30 13F MESA LABS COM 59064R109 3,067 387 14.44 729 11.47 0.0006
2019-08-12 2019-06-30 13F MESA LABS COM 59064R109 2,680 1,791 201.46 654 219.02 0.0005
2019-05-13 2019-03-31 13F MESA LABS COM 59064R109 889 84 10.43 205 22.02 0.0002
2019-02-12 2018-12-31 13F MESA LABS COM 59064R109 805 -121 -13.07 168 -2.33 0.0002
2018-11-13 2018-09-30 13F MESA LABS COM 59064R109 926 450 94.54 172 72.00 0.0002
2018-08-10 2018-06-30 13F MESA LABS COM 59064R109 476 110 30.05 100 85.19 0.0001
2018-05-11 2018-03-31 13F MESA LABS COM 59064R109 366 26 7.65 54 25.58 0.0000
2018-02-12 2017-12-31 13F MESA LABS COM 59064R109 340 340 43 0.0000
2017-11-13 2017-09-30 13F MESA LABS COM 59064R109 0 -21 -100.00 0 -100.00
2017-08-11 2017-06-30 13F MESA LABS COM 59064R109 21 -187 -89.90 3 -88.46 0.0000
2017-05-12 2017-03-31 13F MESA LABS COM 59064R109 208 -2,832 -93.16 26 -93.03 0.0000
2017-02-10 2016-12-31 13F MESA LABS COM 59064R109 3,040 2,793 1,130.77 373 1,232.14 0.0003
2016-11-10 2016-09-30 13F MESA LABS COM 59064R109 247 247 28 0.0000
2016-08-12 2016-06-30 13F MESA LABS COM 59064R109 0 -2,059 -100.00 0 -100.00
2016-05-13 2016-03-31 13F MESA LABS COM 59064R109 2,059 1,874 1,012.97 198 1,000.00 0.0002
2016-02-12 2015-12-31 13F MESA LABS COM 59064R109 185 185 0.00 18 0.0000
2015-11-13 2015-09-30 13F MESA LABS COM 59064R109 0 -38 -100.00 0 -100.00
2015-08-13 2015-06-30 13F MESA LABS COM 59064R109 38 -204 -84.30 3 -82.35 0.0000
2015-05-14 2015-03-31 13F MESA LABS COM 59064R109 242 -237 -49.48 17 -54.05 0.0000
2015-02-17 2014-12-31 13F MESA LABS COM 59064R109 479 381 388.78 37 516.67 0.0000
2014-11-14 2014-09-30 13F MESA LABS COM 59064R109 98 74 308.33 6 200.00 0.0000
2014-08-14 2014-06-30 13F MESA LABS COM 59064R109 24 -506 -95.47 2 -95.83 0.0000
2014-05-15 2014-03-31 13F MESA LABS COM 59064R109 530 -405 -43.32 48 -34.25 0.0000
2014-02-14 2013-12-31 13F MESA LABS COM 59064R109 935 926 10,288.89 73 0.0001
2013-11-14 2013-09-30 13F MESA LABS COM 59064R109 9 -165 -94.83 0 -100.00
2013-08-14 2013-06-30 13F MESA LABS COM 59064R109 174 174 9 0.0000
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.