塞雷斯治療公司

SecurityMCRB / Seres Therapeutics, Inc.
InstitutionSimplex Trading, Llc
Latest Disclosed Ownership3,070 shares
Latest Disclosed Value $ 27,230
Simplex Trading, Llc ownership in MCRB / Seres Therapeutics, Inc.

On May 14, 2026 - Simplex Trading, Llc filed a 13F-HR form disclosing ownership of 3,070 shares of Seres Therapeutics, Inc. (US:MCRB) valued at $27,231 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 11, 2026 disclosing 1,232 shares of Seres Therapeutics, Inc.. This represents a change in shares of 149.19% during the quarter. The current value of the position is $21,030 USD.

Simplex Trading, Llc has a history of taking positions in derivatives of the underlying security (MCRB) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 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.

Upgrade to unlock premium data and export to Excel .

Institutional Put/Call Ratios
(Premium Subscription Required)

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.

MCRB / Seres Therapeutics, 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)
2026-05-14 2026-03-31 13F SERES THERAPEUTICS COM 81750R201 3,070 1,838 149.19 27 50.00 0.0000
2026-02-11 2025-12-31 13F SERES THERAPEUTICS COM 81750R201 1,232 -1,575 -56.11 18 0.0000
2025-11-12 2025-09-30 13F SERES THERAPEUTICS COM 81750R201 2,807 2,807 0 0.0000
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
(%)
2025-08-05 2025-06-30 13F SERES THERAPEUTICS CALL Call 0 -100.00 0 n/a n/a n/a
2025-05-12 2025-03-31 13F SERES THERAPEUTICS CALL Call 52,100 -78.16 0 n/a n/a n/a
2025-02-11 2024-12-31 13F SERES THERAPEUTICS CALL Call 238,500 23.83 0 n/a n/a n/a
2024-11-08 2024-09-30 13F SERES THERAPEUTICS CALL Call 192,600 -29.58 0 n/a n/a n/a
2024-07-25 2024-06-30 13F SERES THERAPEUTICS CALL Call 273,500 251.99 0 n/a n/a n/a
2024-04-25 2024-03-31 13F SERES THERAPEUTICS CALL Call 77,700 286.57 0 n/a n/a n/a
2024-02-02 2023-12-31 13F SERES THERAPEUTICS CALL Call 20,100 -89.91 0 n/a n/a n/a
2023-11-01 2023-09-30 13F SERES THERAPEUTICS CALL Call 199,200 60.77 0 n/a n/a n/a
2023-08-04 2023-06-30 13F SERES THERAPEUTICS CALL Call 123,900 1,177.32 1 n/a n/a n/a
2023-04-27 2023-03-31 13F SERES THERAPEUTICS CALL Call 9,700 -63.26 0 n/a n/a n/a
2023-02-02 2022-12-31 13F SERES THERAPEUTICS CALL Call 26,400 -73.63 0 -100.00 n/a n/a n/a
2022-11-04 2022-09-30 13F SERES THERAPEUTICS CALL Call 100,100 325.96 642 702.50 n/a n/a n/a
2022-08-03 2022-06-30 13F SERES THERAPEUTICS CALL Call 23,500 -5.24 80 -54.55 n/a n/a n/a
2022-05-02 2022-03-31 13F SERES THERAPEUTICS CALL Call 24,800 -24.16 176 -35.29 n/a n/a n/a
2022-02-23 2021-12-31 13F/A SERES THERAPEUTICS CALL Call 32,700 -14.84 272 -68.63 n/a n/a n/a
2022-02-04 2021-12-31 13F SERES THERAPEUTICS CALL Call 38,400 867 n/a n/a n/a
2021-10-28 2021-09-30 13F SERES THERAPEUTICS CALL Call 38,400 -44.59 867 -47.52 n/a n/a n/a
2021-08-12 2021-06-30 13F SERES THERAPEUTICS CALL Call 69,300 6,694.12 1,652 -21.33 n/a n/a n/a
2021-04-26 2021-03-31 13F SERES THERAPEUTICS CALL Call 1,020 2,656.76 2,100 2,233.33 n/a n/a n/a
2021-02-02 2020-12-31 13F SERES THERAPEUTICS CALL Call 37 -46.38 90 -53.85 n/a n/a n/a
2020-10-14 2020-09-30 13F SERES THERAPEUTICS CALL Call 69 -88.67 195 -32.53 n/a n/a n/a
2020-07-13 2020-06-30 13F SERES THERAPEUTICS CALL Call 609 5,990.00 289 9,533.33 n/a n/a n/a
2020-04-29 2020-03-31 13F SERES THERAPEUTICS CALL Call 10 900.00 3 -98.96 n/a n/a n/a
2020-02-05 2019-12-31 13F SERES THERAPEUTICS CALL Call 1 -96.77 0 -100.00 n/a n/a n/a
2019-10-15 2019-09-30 13F SERES THERAPEUTICS CALL Call 31 416.67 12 1,100.00 n/a n/a n/a
2019-07-26 2019-06-30 13F SERES THERAPEUTICS CALL Call 6 500.00 1 -91.67 n/a n/a n/a
2019-04-18 2019-03-31 13F SERES THERAPEUTICS CALL Call 1 -88.89 0 -100.00 n/a n/a n/a
2019-01-16 2018-12-31 13F SERES THERAPEUTICS CALL Call 9 0.00 4 -33.33 n/a n/a n/a
2018-10-23 2018-09-30 13F SERES THERAPEUTICS CALL Call 9 -18.18 6 -33.33 n/a n/a n/a
2018-07-30 2018-06-30 13F SERES THERAPEUTICS CALL Call 11 1,000.00 9 n/a n/a n/a
2018-04-26 2018-03-31 13F SERES THERAPEUTICS CALL Call 1 -97.62 0 -100.00 n/a n/a n/a
2018-01-10 2017-12-31 13F SERES THERAPEUTICS CALL Call 42 20.00 3 -88.00 n/a n/a n/a
2017-10-25 2017-09-30 13F SERES THERAPEUTICS CALL Call 35 -40.68 25 56.25 n/a n/a n/a
2017-07-12 2017-06-30 13F SERES THERAPEUTICS CALL Call 59 -72.43 16 -5.88 n/a n/a n/a
2017-04-21 2017-03-31 13F SERES THERAPEUTICS CALL Call 214 -17.69 17 -5.56 n/a n/a n/a
2017-01-11 2016-12-31 13F SERES THERAPEUTICS CALL Call 260 185.71 18 260.00 n/a n/a n/a
2016-10-07 2016-09-30 13F SERES THERAPEUTICS CALL Call 91 -1.09 5 -81.48 n/a n/a n/a
2016-07-18 2016-06-30 13F SERES THERAPEUTICS CALL Call 92 1.10 27 440.00 n/a n/a n/a
2016-04-14 2016-03-31 13F SERES THERAPEUTICS CALL Call 0 -100.00 0 -100.00 n/a n/a n/a
2016-01-20 2015-12-31 13F SERES THERAPEUTICS CALL Call 2 0 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
(%)
2025-08-05 2025-06-30 13F SERES THERAPEUTICS PUT Put 0 -100.00 0 n/a n/a n/a
2025-05-12 2025-03-31 13F SERES THERAPEUTICS PUT Put 1,700 -98.07 0 n/a n/a n/a
2025-02-11 2024-12-31 13F SERES THERAPEUTICS PUT Put 87,900 -18.69 0 n/a n/a n/a
2024-11-08 2024-09-30 13F SERES THERAPEUTICS PUT Put 108,100 -37.80 0 n/a n/a n/a
2024-07-25 2024-06-30 13F SERES THERAPEUTICS PUT Put 173,800 144.79 0 n/a n/a n/a
2024-04-25 2024-03-31 13F SERES THERAPEUTICS PUT Put 71,000 975.76 0 n/a n/a n/a
2024-02-02 2023-12-31 13F SERES THERAPEUTICS PUT Put 6,600 -89.77 0 n/a n/a n/a
2023-11-01 2023-09-30 13F SERES THERAPEUTICS PUT Put 64,500 -22.38 0 n/a n/a n/a
2023-08-04 2023-06-30 13F SERES THERAPEUTICS PUT Put 83,100 -26.33 0 n/a n/a n/a
2023-04-27 2023-03-31 13F SERES THERAPEUTICS PUT Put 112,800 3,318.18 1 n/a n/a n/a
2023-02-02 2022-12-31 13F SERES THERAPEUTICS PUT Put 3,300 -94.83 0 -100.00 n/a n/a n/a
2022-11-04 2022-09-30 13F SERES THERAPEUTICS PUT Put 63,800 3,257.89 409 6,716.67 n/a n/a n/a
2022-08-03 2022-06-30 13F SERES THERAPEUTICS PUT Put 1,900 -58.70 6 -81.25 n/a n/a n/a
2022-05-02 2022-03-31 13F SERES THERAPEUTICS PUT Put 4,600 -95.17 32 -95.96 n/a n/a n/a
2022-02-23 2021-12-31 13F/A SERES THERAPEUTICS PUT Put 95,200 411.83 793 88.81 n/a n/a n/a
2022-02-04 2021-12-31 13F SERES THERAPEUTICS PUT Put 18,600 420 n/a n/a n/a
2021-10-28 2021-09-30 13F SERES THERAPEUTICS PUT Put 18,600 -6.53 420 -11.39 n/a n/a n/a
2021-08-12 2021-06-30 13F SERES THERAPEUTICS PUT Put 19,900 44,122.22 474 415.22 n/a n/a n/a
2021-04-26 2021-03-31 13F SERES THERAPEUTICS PUT Put 45 18.42 92 -1.08 n/a n/a n/a
2021-02-02 2020-12-31 13F SERES THERAPEUTICS PUT Put 38 -90.64 93 -91.91 n/a n/a n/a
2020-10-14 2020-09-30 13F SERES THERAPEUTICS PUT Put 406 802.22 1,149 5,371.43 n/a n/a n/a
2020-07-13 2020-06-30 13F SERES THERAPEUTICS PUT Put 45 -88.92 21 -98.17 n/a n/a n/a
2020-02-05 2019-12-31 13F SERES THERAPEUTICS PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2019-10-15 2019-09-30 13F SERES THERAPEUTICS PUT Put 10 -89.01 4 -86.21 n/a n/a n/a
2019-07-26 2019-06-30 13F SERES THERAPEUTICS PUT Put 91 727.27 29 314.29 n/a n/a n/a
2019-04-18 2019-03-31 13F SERES THERAPEUTICS PUT Put 11 1,000.00 7 -75.86 n/a n/a n/a
2019-01-16 2018-12-31 13F SERES THERAPEUTICS PUT Put 1 -90.91 0 -100.00 n/a n/a n/a
2018-10-23 2018-09-30 13F SERES THERAPEUTICS PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2018-07-30 2018-06-30 13F SERES THERAPEUTICS PUT Put 6 -25.00 5 n/a n/a n/a
2018-04-26 2018-03-31 13F SERES THERAPEUTICS PUT Put 8 -84.62 0 -100.00 n/a n/a n/a
2018-01-10 2017-12-31 13F SERES THERAPEUTICS PUT Put 52 -92.85 3 -80.00 n/a n/a n/a
2017-10-25 2017-09-30 13F SERES THERAPEUTICS PUT Put 727 2,171.88 15 275.00 n/a n/a n/a
2017-07-12 2017-06-30 13F SERES THERAPEUTICS PUT Put 32 28.00 4 33.33 n/a n/a n/a
2017-04-21 2017-03-31 13F SERES THERAPEUTICS PUT Put 25 -24.24 3 -25.00 n/a n/a n/a
2017-01-11 2016-12-31 13F SERES THERAPEUTICS PUT Put 33 -52.17 4 -85.71 n/a n/a n/a
2016-10-07 2016-09-30 13F SERES THERAPEUTICS PUT Put 69 109.09 28 600.00 n/a n/a n/a
2016-01-20 2015-12-31 13F SERES THERAPEUTICS PUT Put 0 -100.00 0 -100.00 n/a n/a n/a
2015-10-08 2015-09-30 13F SERES THERAPEUTICS PUT Put 2 1 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.