Portolan Capital Management, LLC

Reported holdings as of Q2 2026, from 31 quarterly filings.

Holdings

By sector

Industry comes from the SIC code on each company's own SEC filings, which is self-reported and sometimes out of date. Derivative exposure is counted with the shares. Securities the SEC assigns no industry - funds, trusts, foreign issues - are shown as not classified rather than dropped.

Quarter by quarter

Rows marked UNVERIFIED ID, PLACEHOLDER ID, TICKER AS ID or NON-CUSIP ID carry an identifier that is not a valid CUSIP. They are shown because the filer reported that money, but treat the security named with caution - hover the chip for what is wrong with it, and see the methodology.

Held counts consecutive filings in which this manager reported the position, and can reach further back than the quarters listed above: the tabs begin at Q4 2018 because earlier coverage is too sparse to describe a market, but tenure is counted over every filing we hold, some reaching to 2007. A position sold and later rebought starts again from one.

Weight change is the shift in this position's share of the whole book, in percentage points. It is the more useful column: when money flows into or out of a broad fund, almost every holding is bought or sold at once, so added and trimmed largely track flows. A weight that rose while the book shrank is a decision. Both compare with the previous quarter this filer reported, not the previous calendar quarter.