PROTO LABS INC (PRLB) Stock Institutional Trading Activity


PROTO LABS INC (PRLB) position changes reported by tracked institutional filers across multiple SEC 13F reporting periods. Based on recent SEC 13F filings (Q4 2025), investors with some of the largest reported share count changes include Disciplined Growth Investors, Renaissance Technologies LLC, Polen Capital Management, ARK Invest, and Mairs & Power Growth Fund. Explore insights into buying and selling patterns, position changes, and investment conviction levels to understand institutional trading behavior and market dynamics.

Explore more:

Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q2 2021ARK InvestSell-624,2243,030,630$278,212
Q2 2021Renaissance Technologies LLCBuy102,686161,383$14,815
Q2 2021Mairs & Power Growth FundBuy68,794244,080$22,407
Q2 2021Disciplined Growth InvestorsBuy572,208970,918$89,130
Q1 2021ARK InvestSell-465,0683,654,854$444,978
Q1 2021Renaissance Technologies LLCBuy49,39758,697$7,146
Q1 2021Mairs & Power Growth FundSell-25,224175,286$21,341
Q1 2021Disciplined Growth InvestorsSell-222,767398,710$48,543
Q4 2020ARK InvestBuy1,025,8874,119,922$631,996
Q4 2020Mairs & Power Growth FundSell-2,905200,510$30,758
Q4 2020Disciplined Growth InvestorsSell-24,543621,477$95,335
Q3 2020ARK InvestBuy877,6293,094,035$400,678
Q3 2020Mairs & Power Growth FundSell-10,548203,415$26,342
Q3 2020Disciplined Growth InvestorsSell-18,754646,020$83,660
Q2 2020ARK InvestBuy613,7302,216,406$249,279
Q2 2020Mairs & Power Growth FundSell-15,275213,963$24,064
Q2 2020Disciplined Growth InvestorsSell-239,354664,774$74,767
Q1 2020ARK InvestBuy797,7511,602,676$122,012
Q1 2020Mairs & Power Growth FundSell-1,331229,238$17,452
Q1 2020Disciplined Growth InvestorsSell-16,146904,128$68,831
Q4 2019Mairs & Power Growth FundSell-325230,569$23,414
Q4 2019ARK InvestBuy124,887804,925$81,740
Q4 2019Renaissance Technologies LLCSell-6,4009,300$944
Q4 2019Disciplined Growth InvestorsBuy20,095920,274$93,454
Q3 2019Mairs & Power Growth FundSell-1,285230,894$23,574
Q3 2019ARK InvestBuy209,190680,038$69,432
Q3 2019Renaissance Technologies LLCSell-33,10015,700$1,603
Q3 2019Disciplined Growth InvestorsBuy16,508900,179$91,908
Q2 2019Mairs & Power Growth FundSell-997232,179$26,937
Q2 2019ARK InvestBuy179,626470,848$54,628

Frequently asked questions about PRLB activity

  • Which institutional owners are buying PRLB?

    Institutional owners buying PRLB include investors who have either initiated new positions or increased their existing holdings based on recent SEC 13F filings. The activity table above highlights which funds added shares in the latest reporting periods and how their positions changed over time.

  • What does "buy" mean in PRLB activity?

    "Buy" means an investor increased their reported position in PRLB compared to the prior reporting period. This reflects growing exposure to PROTO LABS INC (PRLB) rather than necessarily a brand-new position (though new positions also appear as buys when prior quantity was zero).

  • Is institutional interest in PRLB increasing?

    Institutional interest in PRLB can be assessed by comparing the number of tracked funds adding or increasing positions versus those trimming or exiting across the periods shown. A higher number of additions typically signals increasing participation among large filers, but it should be read alongside position sizes and the full table.