Cytek Biosciences, Inc.
DE ˙ DB ˙ US23285D1090
3,46 € ↓ -0,08 (-2,26%)
2026-06-04
DEL PRIS
SecurityDE:8EQ / Cytek Biosciences, Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership471,392 shares
Latest Disclosed Value $ 2,059,983
Citadel Advisors Llc ownership in 8EQ / Cytek Biosciences, Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 471,392 shares of Cytek Biosciences, Inc. (DE:8EQ) valued at $1,744,150 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 166,754 shares of Cytek Biosciences, Inc.. This represents a change in shares of 182.69% during the quarter. The current value of the position is $1,631,016 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (8EQ) in the form of stock options. The firm currently holds call options representing 11,500 of underlying shares valued at $50,255 USD and put options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

DE:8EQ / Cytek Biosciences, Inc. Historical Put/Call Ratio
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)
2026-05-15 2026-03-31 13F CYTEK BIOSCIENCES COM 23285D109 471,392 304,638 182.69 2,060 144.54 0.0003
2026-02-17 2025-12-31 13F CYTEK BIOSCIENCES COM 23285D109 166,754 84,450 102.61 842 195.44 0.0001
2025-11-14 2025-09-30 13F CYTEK BIOSCIENCES COM 23285D109 82,304 -534,781 -86.66 286 -86.42 0.0000
2025-08-14 2025-06-30 13F CYTEK BIOSCIENCES COM 23285D109 617,085 14,568 2.42 2,098 -13.16 0.0004
2025-05-15 2025-03-31 13F CYTEK BIOSCIENCES COM 23285D109 602,517 401,377 199.55 2,416 85.13 0.0005
2025-02-14 2024-12-31 13F CYTEK BIOSCIENCES COM 23285D109 201,140 -69,432 -25.66 1,305 -12.88 0.0002
2024-11-14 2024-09-30 13F CYTEK BIOSCIENCES COM 23285D109 270,572 213,444 373.62 1,499 371.07 0.0003
2024-08-14 2024-06-30 13F CYTEK BIOSCIENCES COM 23285D109 57,128 57,128 319 0.0001
2024-02-14 2023-12-31 13F CYTEK BIOSCIENCES COM 23285D109 0 -404 -100.00 0 -100.00
2023-11-14 2023-09-30 13F CYTEK BIOSCIENCES COM 23285D109 404 -755 -65.14 2 -77.78 0.0000
2023-08-14 2023-06-30 13F CYTEK BIOSCIENCES COM 23285D109 1,159 -391,733 -99.71 10 -99.75 0.0000
2023-05-15 2023-03-31 13F CYTEK BIOSCIENCES COM 23285D109 392,892 343,750 699.50 3,611 620.56 0.0008
2023-02-14 2022-12-31 13F CYTEK BIOSCIENCES COM 23285D109 49,142 49,142 502 0.0001
2022-11-14 2022-09-30 13F CYTEK BIOSCIENCES COM 23285D109 0 -264,928 -100.00 0 -100.00
2022-08-15 2022-06-30 13F CYTEK BIOSCIENCES COM 23285D109 264,928 239,579 945.12 2,843 941.39 0.0007
2022-05-16 2022-03-31 13F CYTEK BIOSCIENCES COM 23285D109 25,349 -67,020 -72.56 273 -81.90 0.0001
2022-02-14 2021-12-31 13F CYTEK BIOSCIENCES COM 23285D109 92,369 77,051 503.01 1,508 359.76 0.0003
2021-11-15 2021-09-30 13F CYTEK BIOSCIENCES Cmn 23285D109 15,318 15,318 328 0.0001
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F CYTEK BIOSCIENCES COM Call 11,500 50 n/a n/a n/a
2025-08-14 2025-06-30 13F CYTEK BIOSCIENCES COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-05-15 2025-03-31 13F CYTEK BIOSCIENCES COM Call 600 -40.00 2 -66.67 n/a n/a n/a
2025-02-14 2024-12-31 13F CYTEK BIOSCIENCES COM Call 1,000 150.00 6 200.00 n/a n/a n/a
2024-11-14 2024-09-30 13F CYTEK BIOSCIENCES COM Call 400 100.00 2 100.00 n/a n/a n/a
2024-08-14 2024-06-30 13F CYTEK BIOSCIENCES COM Call 200 1 n/a n/a n/a
2024-02-14 2023-12-31 13F CYTEK BIOSCIENCES COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2023-11-14 2023-09-30 13F CYTEK BIOSCIENCES COM Call 6,100 -76.54 34 -85.14 n/a n/a n/a
2023-08-14 2023-06-30 13F CYTEK BIOSCIENCES COM Call 26,000 13.54 222 5.71 n/a n/a n/a
2023-05-15 2023-03-31 13F CYTEK BIOSCIENCES COM Call 22,900 -62.27 210 -66.07 n/a n/a n/a
2023-02-14 2022-12-31 13F CYTEK BIOSCIENCES COM Call 60,700 -12.16 620 -39.13 n/a n/a n/a
2022-11-14 2022-09-30 13F CYTEK BIOSCIENCES COM Call 69,100 1,017 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2025-08-14 2025-06-30 13F CYTEK BIOSCIENCES COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-05-15 2025-03-31 13F CYTEK BIOSCIENCES COM Put 4,900 20 n/a n/a n/a
2024-11-14 2024-09-30 13F CYTEK BIOSCIENCES COM Put 0 -100.00 0 n/a n/a n/a
2024-08-14 2024-06-30 13F CYTEK BIOSCIENCES COM Put 100 1 n/a n/a n/a
2024-02-14 2023-12-31 13F CYTEK BIOSCIENCES COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2023-11-14 2023-09-30 13F CYTEK BIOSCIENCES COM Put 9,300 158.33 51 70.00 n/a n/a n/a
2023-08-14 2023-06-30 13F CYTEK BIOSCIENCES COM Put 3,600 3,500.00 31 n/a n/a n/a
2023-05-15 2023-03-31 13F CYTEK BIOSCIENCES COM Put 100 -66.67 1 -100.00 n/a n/a n/a
2023-02-14 2022-12-31 13F CYTEK BIOSCIENCES COM Put 300 3 n/a n/a n/a
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.