Thermo Fisher Scientific Inc.
MX ˙ BMV ˙ US8835561023
SecurityMX:TMO / Thermo Fisher Scientific Inc.
InstitutionCalamos Advisors LLC
Latest Disclosed Ownership139,230 shares
Latest Disclosed Value $ 68,435,722
Calamos Advisors LLC ownership in TMO / Thermo Fisher Scientific Inc.

On May 4, 2026 - Calamos Advisors LLC filed a 13F-HR form disclosing ownership of 139,230 shares of Thermo Fisher Scientific Inc. (MX:TMO) valued at $68,435,722 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 29, 2026 disclosing 169,900 shares of Thermo Fisher Scientific Inc.. This represents a change in shares of -18.05% during the quarter.

Calamos Advisors LLC 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)
2026-05-04 2026-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 139,230 -30,670 -18.05 68,436 -30.49 0.2414
2026-01-29 2025-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 169,900 22,200 15.03 98,449 37.43 0.3698
2025-10-20 2025-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 147,700 27,510 22.89 71,637 47.00 0.2646
2025-08-08 2025-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 120,190 -22,500 -15.77 48,732 -31.37 0.1918
2025-04-29 2025-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 142,690 -3,110 -2.13 71,003 -6.39 0.3091
2025-01-24 2024-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 145,800 3,458 2.43 75,850 -13.85 0.3172
2024-11-07 2024-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 142,342 1,672 1.19 88,048 13.19 0.3807
2024-07-25 2024-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 140,670 -3,011 -2.10 77,791 -6.85 0.3455
2024-05-08 2024-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 143,681 58 0.04 83,509 9.54 0.3956
2024-01-31 2023-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 143,623 -23,327 -13.97 76,234 -9.79 0.3698
2023-10-26 2023-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 166,950 7,011 4.38 84,505 1.27 0.4390
2023-07-28 2023-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 159,939 12,622 8.57 83,448 -1.72 0.4129
2023-05-04 2023-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 147,317 -11,999 -7.53 84,909 -3.22 0.4147
2023-01-26 2022-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 159,316 -37,886 -19.21 87,734 -12.28 0.4116
2022-10-24 2022-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 197,202 10,783 5.78 100,019 -1.24 0.4575
2022-08-01 2022-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 186,419 9,333 5.27 101,278 -3.17 0.4368
2022-05-03 2022-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 177,086 4,401 2.55 104,596 -9.22 0.3927
2022-02-01 2021-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 172,685 40,532 30.67 115,222 52.61 0.4308
2021-10-26 2021-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 132,153 35,890 37.28 75,503 55.48 0.3298
2021-07-22 2021-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 96,263 -12,858 -11.78 48,562 -2.49 0.2219
2021-04-12 2021-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 109,121 -34,820 -24.19 49,801 -25.72 0.2717
2021-01-27 2020-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 143,941 6,691 4.88 67,045 10.64 0.3891
2020-10-26 2020-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 137,250 43,231 45.98 60,599 77.88 0.3900
2020-07-27 2020-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 94,019 -2,962 -3.05 34,067 23.86 0.2408
2020-04-28 2020-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 96,981 -42,086 -30.26 27,504 -39.12 0.2158
2020-01-15 2019-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 139,067 -1,133 -0.81 45,179 10.64 0.2234
2019-10-21 2019-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 140,200 5,131 3.80 40,836 2.95 0.2224
2019-08-07 2019-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 135,069 2,618 1.98 39,667 9.41 0.2202
2019-04-12 2019-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 132,451 -11 -0.01 36,254 22.30 0.2262
2019-01-24 2018-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 132,462 6,769 5.39 29,644 -3.37 0.1957
2018-10-22 2018-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 125,693 -18,165 -12.63 30,679 2.95 0.1688
2018-07-17 2018-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 143,858 -2,061 -1.41 29,799 -1.09 0.1821
2018-04-13 2018-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 145,919 2,643 1.84 30,127 10.74 0.1960
2018-02-13 2017-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 143,276 -3,988 -2.71 27,205 -2.36 0.1387
2017-10-25 2017-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 147,264 2,267 1.56 27,862 10.14 0.2155
2017-08-09 2017-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 144,997 -21,685 -13.01 25,298 -1.19 0.1870
2017-04-20 2017-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 166,682 83,598 100.62 25,602 118.39 0.2016
2017-02-06 2016-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 83,084 -1,158 -1.37 11,723 -12.51 0.0932
2016-11-14 2016-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 84,242 236 0.28 13,400 7.95 0.0958
2016-07-26 2016-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 84,006 -25,369 -23.19 12,413 -19.84 0.0871
2016-04-25 2016-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 109,375 31,200 39.91 15,486 39.65 0.1027
2016-02-05 2015-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 78,175 1,218 1.58 11,089 17.84 0.0705
2015-11-10 2015-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 76,957 27 0.04 9,410 -5.73 0.0648
2015-08-14 2015-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 76,930 -4,340 -5.34 9,982 -8.57 0.0617
2015-05-13 2015-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 81,270 48 0.06 10,918 7.29 0.0684
2015-02-13 2014-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 81,222 422 0.52 10,176 3.49 0.0673
2014-11-14 2014-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 80,800 0 0.00 9,833 3.14 0.0656
2014-08-14 2014-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 80,800 5,800 7.73 9,534 5.72 0.0604
2014-05-16 2014-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 75,000 0 0.00 9,018 7.99 0.0576
2014-02-14 2013-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 75,000 0 0.00 8,351 20.84 0.0531
2013-11-14 2013-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 75,000 30,000 66.67 6,911 81.49 0.0433
2013-08-12 2013-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 45,000 45,000 3,808 0.0249
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
(%)
2025-10-20 2025-09-30 13F THERMO FISHER SCIENTIFIC COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-08-08 2025-06-30 13F THERMO FISHER SCIENTIFIC COM Put 16,000 7,962 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.