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.

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Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q4 2016Mairs & Power Growth FundBuy6,445374,044$19,207
Q4 2016ARK InvestBuy176,335176,335$9,055
Q4 2016Disciplined Growth InvestorsBuy970,600970,600$49,840
Q3 2016Mairs & Power Growth FundBuy52,520367,599$22,023
Q2 2016Mairs & Power Growth FundBuy65,785315,079$18,136
Q1 2016Mairs & Power Growth FundBuy31,075249,294$19,218
Q1 2016Renaissance Technologies LLCSell-2,6003,300$254
Q4 2015Mairs & Power Growth FundBuy169,775218,219$13,898
Q4 2015Renaissance Technologies LLCSell-71,6005,900$376
Q3 2015Mairs & Power Growth FundSell-2,33048,444$3,246
Q3 2015Renaissance Technologies LLCBuy77,50077,500$5,193
Q2 2015Mairs & Power Growth FundSell-2,03050,774$3,426
Q1 2015Mairs & Power Growth FundBuy2,68052,804$3,696
Q4 2014Mairs & Power Growth FundBuy10,57750,124$3,366
Q3 2014Mairs & Power Growth FundBuy64339,547$2,729
Q2 2014Mairs & Power Growth FundBuy3,80038,904$3,187
Q2 2014Sequoia Financial AdvisorsBuy303,018$247
Q1 2014Mairs & Power Growth FundBuy8,40035,104$2,375
Q1 2014Sequoia Financial AdvisorsBuy2,9882,988$202
Q4 2013Mairs & Power Growth FundBuy5,30026,704$1,901
Q2 2013Mairs & Power Growth FundBuy21,40421,404$1,391

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.