Sutro Biopharma, Inc.: shareholders and insiders

STRONASDAQHealthcare · Biological Products, (No Diagnostic Substances)

Price

$9.82

November 13, 2026Market cap $163M

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  • The full history: 10 fiscal years, from 2016
  • The estimated fair value, with its range and its certainty
  • The full analysis, 18 a month
  • More questions to the chat on its filings
  • Excel with every year
  • An email when it reports, changes its dividend or an officer buys

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Insiders and their shares

Purchases and sales by officers and directors, from their own Form 4 filings.

Reading the newest filings from the SEC. This part fills in on its own in a few seconds.

Major holders (over 5%)

Whoever comes to own more than 5% of a class of shares reports it to the SEC on Schedule 13D or 13G. Here is each holder's latest filing.

6 Holders over 5%Nov 9, 2026 Latest filing
  • Perceptive Advisors LLCwith 2 more persons
    Share of class7.90%
  • Biotechnology Value Fund L Pwith 9 more persons
    Share of class7.60%
  • Affinity Asset Advisors, LLCwith 1 more person
    Share of class6.50%
  • BlackRock, Inc.
    Share of class6.40%
  • Samsara BioCapital, L.P.with 4 more persons
    Share of class6.40%
  • Coastlands Capital LPwith 4 more persons
    Share of class5.14%
Fell to 5% or less (6)

Holders whose latest filing says they hold 5% or less. After it they need not file again, so what they hold today is not known.

  • Point72 Asset Management, L.P.1.40%Aug 14, 202613G/A
  • Kynam Capital Management, LP5.27%May 15, 202613G/A
  • Millennium Management LLC1.30%Apr 21, 202613G/A
  • Suvretta Capital Management0.00%Feb 13, 202613G/A
  • RA Capital Management, L.P.0.00%Aug 14, 202513G/A
  • The Vanguard Group4.87%Jul 29, 202513G/A

From the Schedule 13D and 13G filed with the SEC since Dec 18, 2024, when they became structured data. A holder who has filed nothing since then is not shown here. A 13D is updated within two business days of any material change, a 13G up to 45 days after the quarter of the change, so the shares are those of the filing. The large managers also appear in the 13Fs.

Well-known managers

Which of the about 30 investment managers we track held the shares at the quarter end, and what they changed from the quarter before.

Sep 30, 2026 quarter end
  • Point72 (Cohen)
    In the quarter-66%
  • Millennium Mgmt (Englander)
    In the quarter+74%
  • Citadel Advisors (Griffin)
    In the quarter-13%
  • D.E. Shaw
    In the quarter
  • Renaissance Technologies
    In the quarter+1.1%
  • AQR Capital
    In the quarter

From the 13Fs managers file with the SEC up to 45 days after each quarter end. They show only long positions on that day, not short sales or what has changed since. No recent 13F: Pershing Square (Ackman), Scion (Burry).

Short interest

How many of the company's shares have been sold borrowed and not yet bought back, twice a month.

On Oct 15, 2026, 11.8% of its shares outstanding were held short, +6.1% since the report before.

Shares held short
1.96M
11.8%
Since the report before1.85M on Sep 30, 2026
+6.1%
6.3
313.1K
More days to cover thanof 4,578 US-listed companies with enough volume
72%
Report date
Oct 15, 2026
  • Oct 31, 2023: Shares held short 2.37M
  • Nov 15, 2023: Shares held short 2.30M
  • Nov 30, 2023: Shares held short 2.07M
  • Dec 15, 2023: Shares held short 1.90M
  • Dec 29, 2023: Shares held short 2.36M
  • Jan 12, 2024: Shares held short 2.40M
  • Jan 31, 2024: Shares held short 2.61M
  • Feb 15, 2024: Shares held short 2.67M
  • Feb 29, 2024: Shares held short 2.41M
  • Mar 15, 2024: Shares held short 2.32M
  • Mar 28, 2024: Shares held short 2.41M
  • Apr 15, 2024: Shares held short 2.18M
  • Apr 30, 2024: Shares held short 1.95M
  • May 15, 2024: Shares held short 1.95M
  • May 31, 2024: Shares held short 1.90M
  • Jun 14, 2024: Shares held short 2.29M
  • Jun 28, 2024: Shares held short 3.23M
  • Jul 15, 2024: Shares held short 3.70M
  • Jul 31, 2024: Shares held short 3.19M
  • Aug 15, 2024: Shares held short 3.39M
  • Aug 30, 2024: Shares held short 3.02M
  • Sep 13, 2024: Shares held short 2.99M
  • Sep 30, 2024: Shares held short 2.86M
  • Oct 15, 2024: Shares held short 2.86M
  • Oct 31, 2024: Shares held short 2.40M
  • Nov 15, 2024: Shares held short 1.79M
  • Nov 29, 2024: Shares held short 2.06M
  • Dec 13, 2024: Shares held short 2.46M
  • Dec 31, 2024: Shares held short 3.15M
  • Jan 15, 2025: Shares held short 3.85M
  • Jan 31, 2025: Shares held short 4.07M
  • Feb 14, 2025: Shares held short 4.41M
  • Feb 28, 2025: Shares held short 4.46M
  • Mar 14, 2025: Shares held short 4.64M
  • Mar 31, 2025: Shares held short 5.36M
  • Apr 15, 2025: Shares held short 5.42M
  • Apr 30, 2025: Shares held short 5.34M
  • May 15, 2025: Shares held short 6.86M
  • May 30, 2025: Shares held short 5.63M
  • Jun 13, 2025: Shares held short 7.56M
  • Jun 30, 2025: Shares held short 3.66M
  • Jul 15, 2025: Shares held short 3.66M
  • Jul 31, 2025: Shares held short 3.38M
  • Aug 15, 2025: Shares held short 3.53M
  • Aug 29, 2025: Shares held short 3.11M
  • Sep 15, 2025: Shares held short 2.52M
  • Sep 30, 2025: Shares held short 2.48M
  • Oct 15, 2025: Shares held short 2.51M
  • Oct 31, 2025: Shares held short 3.39M
  • Nov 14, 2025: Shares held short 3.52M
  • Nov 28, 2025: Shares held short 3.98M
  • Dec 15, 2025: Shares held short 560.3K
  • Dec 31, 2025: Shares held short 404.8K
  • Jan 15, 2026: Shares held short 528.2K
  • Jan 30, 2026: Shares held short 591.3K
  • Feb 13, 2026: Shares held short 645.1K
  • Feb 27, 2026: Shares held short 517.4K
  • Mar 13, 2026: Shares held short 532.6K
  • Mar 31, 2026: Shares held short 639.7K
  • Apr 15, 2026: Shares held short 748.7K
  • Apr 30, 2026: Shares held short 977.1K
  • May 15, 2026: Shares held short 1.19M
  • May 29, 2026: Shares held short 751.4K
  • Jun 15, 2026: Shares held short 922.2K
  • Jun 30, 2026: Shares held short 1.36M
  • Jul 15, 2026: Shares held short 1.65M
  • Jul 31, 2026: Shares held short 1.74M
  • Aug 14, 2026: Shares held short 1.86M
  • Aug 31, 2026: Shares held short 1.81M
  • Sep 15, 2026: Shares held short 2.08M
  • Sep 30, 2026: Shares held short 1.85M
  • Oct 15, 2026: Shares held short 1.96M

As brokers report them to the regulator twice a month, mid-month and at month end, published about eight business days later. A short position is shares sold borrowed and not yet bought back. The share count is the one the company's market value is figured on, from its filings. Days to cover is the shares held short over the average daily volume of the weeks between two reports.

Short sales in daily trading40.5% of the shares in the last 14 sessions' reported trades were short sales.

In the last 14 sessions, 40.5% of the shares in the reported trades were short sales, against 59.5% in the 14 before.

Last 14 sessionsOct 27, 2026 – Nov 13, 2026
40.5%
The 14 beforeOct 7, 2026 – Oct 26, 2026
59.5%
Change
-19.0 pts
Short sales a dayon average, of 120.1K shares
48.6K
More than atof 3,649 US-listed companies, same days
20%
Median of alleight in ten from 34.6% to 63.4%
50.1%
  • Oct 7, 2026: Short sales 64.9%
  • Oct 8, 2026: Short sales 49.8%
  • Oct 9, 2026: Short sales 78.2%
  • Oct 12, 2026: Short sales 37.2%
  • Oct 13, 2026: Short sales 56.7%
  • Oct 14, 2026: Short sales 54.6%
  • Oct 15, 2026: Short sales 65.3%
  • Oct 16, 2026: Short sales 60%
  • Oct 19, 2026: Short sales 56.3%
  • Oct 20, 2026: Short sales 54.4%
  • Oct 21, 2026: Short sales 74.6%
  • Oct 22, 2026: Short sales 74.1%
  • Oct 23, 2026: Short sales 65.1%
  • Oct 26, 2026: Short sales 56.9%
  • Oct 27, 2026: Short sales 32.8%
  • Oct 28, 2026: Short sales 25.8%
  • Oct 29, 2026: Short sales 35%
  • Oct 30, 2026: Short sales 60.5%
  • Nov 2, 2026: Short sales 71.4%
  • Nov 3, 2026: Short sales 43.9%
  • Nov 4, 2026: Short sales 62.2%
  • Nov 5, 2026: Short sales 9.9%
  • Nov 6, 2026: Short sales 42.2%
  • Nov 9, 2026: Short sales 58.4%
  • Nov 10, 2026: Short sales 54.4%
  • Nov 11, 2026: Short sales 57.4%
  • Nov 12, 2026: Short sales 78.5%
  • Nov 13, 2026: Short sales 62.9%

This is not the number of shares sold short today: it measures short sales within each day's trading, and only trades made off the exchanges. Much of it is market makers, who sell shares they do not have to fill buyers' orders and cover soon after, so for a heavily traded stock the share is often around half.

The ETFs that hold it

Which of the 269 US equity ETFs we track hold the stock, and at what weight, from the funds' N-PORT filings.

7 ETFs holding it0.02% The largest weight (IWN)
  • IWNiShares Russell 2000 Value ETF
    Weight in the fund0.02%
  • IWMiShares Russell 2000 ETF
    Weight in the fund0.01%
  • VTWOVanguard Russell 2000 Index Fund
    Weight in the fund0.01%
  • VXFVanguard Extended Market Index Fund
    Weight in the fund0.01%
  • VHTVanguard Health Care Index Fund
    Weight in the fund0.00%
  • IWOiShares Russell 2000 Growth ETF
    Weight in the fund0.00%
  • VTIVanguard Total Stock Market Index Fund
    Weight in the fund0.00%

7 of the 269 ETFs we track, not of every ETF on the market. The ten largest weights. Positions as each fund filed them in its latest N-PORT.

Institutional investors by quarter

Every manager that reports positions to the SEC (Form 13F), quarter by quarter: how many hold the stock, how many shares and dollars between them, and who entered, left, added or trimmed during the quarter.

101 Managers, Q2 2026$546M Value of their positions
  • Q3 2025: Managers 88
  • Q4 2025: Managers 63
  • Q1 2026: Managers 79
  • Q2 2026: Managers 101

Institutional investors by quarter

The fund managers holding STRO, quarter by quarter, from Q3 2018 to Q2 2025, 28 more quarters

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Q2 2026: 101 managers held 16.50M shares, worth $546M. During the quarter 40 opened a position, 19 closed one, 24 added and 16 trimmed.

The largest holders, Q2 2026

  • Perceptive Advisors
    In the quarter+82%
  • Bvf
    In the quarter
  • Affinity Asset Advisors
    In the quarter+9.6%
  • BlackRock
    In the quarter+382%
  • Samsara Biocapital
    In the quarter
  • Kynam Capital Management
    In the quarter
  • Orbimed Advisors
    In the quarter-7.1%
  • Balyasny Asset Management
    In the quarter+53%
  • Vanguard Capital Management
    In the quarter-3.6%
  • Eventide Asset Management
    In the quarter-18%

From the SEC's Form 13F data sets, Q3 2025 to Q2 2026: the long positions of every manager with more than $100 million under management, as filed up to 45 days after each quarter end. Short positions and options are not in them. Shares as reported each quarter, not adjusted for splits. The stock is matched by its CUSIP, through the SEC's fails-to-deliver files.

Pay against performance, the say-on-pay vote, buybacks by quarter and trading plans are read for S&P 500 companies only.

The full analysis

What do Sutro Biopharma's filings show?

Who buys and sells is one part of Sutro Biopharma's picture. The full Ploutos AI analysis reads everything the company has filed and shows what stands behind it, with a source for every figure.

  • A fair value range built from the filings
  • Earnings quality, debt and red flags
  • Insider and institutional moves
  • The case for and the case against

Questions about STRO's shareholders

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Ask us
Which well-known managers hold STRO?

6 of the managers we track held the shares on Sep 30, 2026. The largest position was Millennium Mgmt (Englander)'s, worth $12M.

Is every insider transaction a purchase or a sale?

No. Many are part of their pay: share awards, option exercises and shares the company keeps for the tax. Only code P is a purchase with their own money, and code S a sale on the market.

Related pages

The other pages on US stocks, free to read. On the company pages, the last three fiscal years are open to everyone, five with a free account, and every year with Ploutos Investor.

US stocksThe market today, the sectors, the largest companies and the week's results.The market's sectorsThe 11 sectors side by side: returns, share of the market, median P/E and dividend.Compare stocksTwo companies side by side: price over up to ten years, with and without dividends, and every figure.US dividend stocksEach dividend's yield next to whether the company's cash covers it and whether it was ever cut.

The figures come from the company's SEC filings and the share price, and describe what it has reported. They are not a score or a fair value.