Mesa Laboratories, Inc.
US ˙ NasdaqGS ˙ US59064R1095

SecurityMLAB / Mesa Laboratories, Inc.
InstitutionRenaissance Technologies Llc
ManagerJames Simons
Latest Disclosed Ownership31,600 shares
Latest Disclosed Value $ 2,794,072
Renaissance Technologies Llc reports 802.86% increase in ownership of MLAB / Mesa Laboratories, Inc.

On May 14, 2026 - Renaissance Technologies Llc filed a 13F-HR form disclosing ownership of 31,600 shares of Mesa Laboratories, Inc. (US:MLAB) valued at $2,794,072 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 3,500 shares of Mesa Laboratories, Inc.. This represents a change in shares of 802.86% during the quarter. The current value of the position is $3,282,924 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 MESA LABS COM 59064R109 31,600 28,100 802.86 2,794 919.71 0.0044
2026-02-12 2025-12-31 13F MESA LABS COM 59064R109 3,500 -7,400 -67.89 275 -62.47 0.0004
2025-11-13 2025-09-30 13F MESA LABS COM 59064R109 10,900 -57,127 -83.98 730 -88.61 0.0010
2025-08-13 2025-06-30 13F MESA LABS COM 59064R109 68,027 59,827 729.60 6,410 558.68 0.0085
2025-05-14 2025-03-31 13F MESA LABS COM 59064R109 8,200 700 9.33 973 -1.62 0.0015
2025-02-13 2024-12-31 13F MESA LABS COM 59064R109 7,500 -5,900 -44.03 989 -43.16 0.0015
2024-11-13 2024-09-30 13F MESA LABS COM 59064R109 13,400 11,000 458.33 1,740 736.54 0.0026
2024-08-09 2024-06-30 13F MESA LABS COM 59064R109 2,400 -13,700 -85.09 208 20,700.00 0.0004
2024-05-13 2024-03-31 13F MESA LABS COM 59064R109 16,100 -14,300 -47.04 2 -66.67 0.0028
2024-02-13 2023-12-31 13F MESA LABS COM 59064R109 30,400 21,600 245.45 3 0.0049
2023-11-14 2023-09-30 13F MESA LABS COM 59064R109 8,800 -14,200 -61.74 1 -100.00 0.0016
2023-08-11 2023-06-30 13F MESA LABS COM 59064R109 23,000 13,300 137.11 3 100.00 0.0043
2023-05-12 2023-03-31 13F MESA LABS COM 59064R109 9,700 -8,234 -45.91 2 -50.00 0.0022
2023-02-13 2022-12-31 13F MESA LABS COM 59064R109 17,934 9,734 118.71 3 -99.83 0.0041
2022-11-14 2022-09-30 13F MESA LABS COM 59064R109 8,200 -4,900 -37.40 1,155 -56.77 0.0016
2022-08-12 2022-06-30 13F MESA LABS COM 59064R109 13,100 0 0.00 2,672 -19.98 0.0032
2022-05-13 2022-03-31 13F MESA LABS COM 59064R109 13,100 -2,782 -17.52 3,339 -35.92 0.0039
2022-02-11 2021-12-31 13F MESA LABS COM 59064R109 15,882 -11,218 -41.39 5,211 -36.40 0.0065
2021-11-12 2021-09-30 13F MESA LABS COM 59064R109 27,100 3,400 14.35 8,194 27.49 0.0106
2021-08-13 2021-06-30 13F MESA LABS COM 59064R109 23,700 11,800 99.16 6,427 121.77 0.0080
2021-05-13 2021-03-31 13F MESA LABS COM 59064R109 11,900 -2,200 -15.60 2,898 -28.30 0.0036
2021-02-10 2020-12-31 13F MESA LABS COM 59064R109 14,100 -28,000 -66.51 4,042 -62.31 0.0044
2020-11-13 2020-09-30 13F MESA LABS COM 59064R109 42,100 -7,000 -14.26 10,725 0.75 0.0107
2020-08-13 2020-06-30 13F MESA LABS COM 59064R109 49,100 15,200 44.84 10,645 38.90 0.0092
2020-05-14 2020-03-31 13F MESA LABS COM 59064R109 33,900 -32,000 -48.56 7,664 -53.37 0.0074
2020-02-13 2019-12-31 13F MESA LABS COM 59064R109 65,900 -14,600 -18.14 16,435 -14.13 0.0126
2019-11-13 2019-09-30 13F MESA LABS COM 59064R109 80,500 33,700 72.01 19,140 67.38 0.0162
2019-08-12 2019-06-30 13F MESA LABS COM 59064R109 46,800 -7,100 -13.17 11,435 -7.96 0.0101
2019-05-14 2019-03-31 13F MESA LABS COM 59064R109 53,900 -8,400 -13.48 12,424 -4.31 0.0113
2019-02-12 2018-12-31 13F MESA LABS COM 59064R109 62,300 -400 -0.64 12,983 11.56 0.0142
2018-11-13 2018-09-30 13F MESA LABS COM 59064R109 62,700 200 0.32 11,638 -11.79 0.0120
2018-08-13 2018-06-30 13F/A-1 MESA LABS COM 59064R109 62,500 -11,500 -15.54 13,193 20.10 0.0144
2018-08-13 2018-06-30 13F MESA LABS COM 59064R109 74,000 10,985
2018-05-14 2018-03-31 13F MESA LABS COM 59064R109 74,000 -4,600 -5.85 10,985 12.44 0.0120
2018-02-13 2017-12-31 13F MESA LABS COM 59064R109 78,600 -5,600 -6.65 9,770 -22.29 0.0108
2017-11-13 2017-09-30 13F MESA LABS COM 59064R109 84,200 -3,071 -3.52 12,573 0.53 0.0148
2017-08-11 2017-06-30 13F MESA LABS COM 59064R109 87,271 7,771 9.77 12,507 28.21 0.0160
2017-05-12 2017-03-31 13F MESA LABS COM 59064R109 79,500 -3,800 -4.56 9,755 -4.60 0.0136
2017-02-13 2016-12-31 13F MESA LABS COM 59064R109 83,300 -10,859 -11.53 10,225 -5.04 0.0162
2016-11-14 2016-09-30 13F MESA LABS COM 59064R109 94,159 -7,441 -7.32 10,768 -13.84 0.0190
2016-08-12 2016-06-30 13F MESA LABS COM 59064R109 101,600 -34,800 -25.51 12,497 -4.91 0.0238
2016-05-13 2016-03-31 13F MESA LABS COM 59064R109 136,400 -2,199 -1.59 13,142 -4.71 0.0250
2016-02-11 2015-12-31 13F MESA LABS COM 59064R109 138,599 4,199 3.12 13,791 -7.89 0.0301
2015-11-12 2015-09-30 13F MESA LABS COM 59064R109 134,400 207 0.15 14,972 25.50 0.0357
2015-08-14 2015-06-30 13F MESA LABS COM 59064R109 134,193 -5,907 -4.22 11,930 17.94 0.0272
2015-05-13 2015-03-31 13F MESA LABS COM 59064R109 140,100 -7,124 -4.84 10,115 -11.13 0.0215
2015-02-13 2014-12-31 13F MESA LABS COM 59064R109 147,224 -20,576 -12.26 11,382 17.40 0.0275
2014-11-12 2014-09-30 13F MESA LABS COM 59064R109 167,800 7,200 4.48 9,695 -28.10 0.0265
2014-08-13 2014-06-30 13F MESA LABS COM 59064R109 160,600 26,457 19.72 13,484 11.38 0.0314
2014-05-14 2014-03-31 13F MESA LABS COM 59064R109 134,143 7,955 6.30 12,106 22.09 0.0290
2014-02-14 2013-12-31 13F MESA LABS COM 59064R109 126,188 14,988 13.48 9,916 31.90 0.0237
2013-11-13 2013-09-30 13F MESA LABS COM 59064R109 111,200 22,000 24.66 7,518 55.72 0.0182
2013-08-12 2013-06-30 13F MESA LABS COM 59064R109 89,200 89,200 4,828 0.0127
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.