Thermo Fisher Scientific Inc.
MX ˙ BMV ˙ US8835561023
SecurityMX:TMO / Thermo Fisher Scientific Inc.
InstitutionMarex Group plc
Latest Disclosed Ownership2,408 shares
Latest Disclosed Value $ 1,183,605
Marex Group plc ownership in TMO / Thermo Fisher Scientific Inc.

On May 13, 2026 - Marex Group plc filed a 13F-HR form disclosing ownership of 2,408 shares of Thermo Fisher Scientific Inc. (MX:TMO) valued at $1,183,605 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 1,283 shares of Thermo Fisher Scientific Inc.. This represents a change in shares of 87.69% during the quarter.

Marex Group plc has a history of taking positions in derivatives of the underlying security (TMO) in the form of stock options.

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.

MX:TMO / Thermo Fisher Scientific 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)
2026-05-13 2026-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 2,408 1,125 87.69 1,184 59.22 0.0075
2026-02-12 2025-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 1,283 -80,147 -98.42 743 -98.12 0.0047
2025-11-14 2025-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 81,430 -19,006 -18.92 39,495 -3.03 0.2791
2025-08-19 2025-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 100,436 -21,418 -17.58 40,730 -32.83 0.3533
2026-04-02 2025-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 121,854 914 0.76 60,635 -3.63 1.1619
2026-04-02 2024-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 120,940 916 0.76 62,917 -15.26 1.0717
2026-04-07 2024-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 120,024 8 0.01 74,243 11.87 1.6935
2026-04-02 2024-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 120,016 -2,484 -2.03 66,369 -6.78 1.7819
2026-04-02 2024-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 122,500 122,500 71,198 2.3138
2026-04-02 2023-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 0 -10,137 -100.00 0 -100.00
2026-04-02 2022-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 10,137 10,137 5,646 0.8021
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
(%)
2026-02-12 2025-12-31 13F THERMO FISHER SCIENTIFIC COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-11-14 2025-09-30 13F THERMO FISHER SCIENTIFIC COM Put 80,000 -15.79 38,802 0.73 n/a n/a n/a
2025-08-19 2025-06-30 13F THERMO FISHER SCIENTIFIC COM Put 95,000 38,519 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.