Thermo Fisher Scientific Inc.
MX ˙ BMV ˙ US8835561023
SecurityMX:TMO / Thermo Fisher Scientific Inc.
InstitutionCapital World Investors
Latest Disclosed Ownership6,646,316 shares
Latest Disclosed Value $ 3,266,681,244
Capital World Investors reports 39.60% decrease in ownership of TMO / Thermo Fisher Scientific Inc.

On May 13, 2026 - Capital World Investors filed a 13F-HR form disclosing ownership of 6,646,316 shares of Thermo Fisher Scientific Inc. (MX:TMO) valued at $3,266,681,244 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 11, 2026 disclosing 11,003,814 shares of Thermo Fisher Scientific Inc.. This represents a change in shares of -39.60% during the quarter.

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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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 6,646,316 -4,357,498 -39.60 3,266,681 -48.77 0.4457
2026-02-11 2025-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 11,003,814 718,669 6.99 6,376,229 27.83 0.8672
2025-11-13 2025-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 10,285,145 706,572 7.38 4,988,132 28.44 0.6814
2025-08-13 2025-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 9,578,573 -1,482,827 -13.41 3,883,769 -29.44 0.5645
2025-05-12 2025-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 11,061,400 1,631,280 17.30 5,504,190 12.20 0.8918
2025-02-13 2024-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 9,430,120 104,343 1.12 4,905,812 -14.96 0.7448
2024-11-13 2024-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 9,325,777 -192,659 -2.02 5,768,589 9.59 0.8943
2024-08-13 2024-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 9,518,436 -3,975,416 -29.46 5,263,668 -32.89 0.8583
2024-05-14 2024-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 13,493,852 1,231,059 10.04 7,842,762 20.49 1.2980
2024-02-13 2023-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 12,262,793 -492,214 -3.86 6,508,990 0.82 1.1576
2023-11-13 2023-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 12,755,007 -121,091 -0.94 6,456,169 -3.90 1.2789
2023-08-11 2023-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 12,876,098 -48,366 -0.37 6,718,028 -9.81 1.2921
2023-05-15 2023-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 12,924,464 -620,777 -4.58 7,449,136 -0.14 1.5397
2023-02-14 2022-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 13,545,241 57,180 0.42 7,459,295 9.04 1.5901
2022-11-14 2022-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 13,488,061 -501,558 -3.59 6,841,108 -9.99 1.5359
2022-08-15 2022-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 13,989,619 -177,932 -1.26 7,600,205 -9.18 1.6146
2022-05-19 2022-03-31 13F/A-1 THERMO FISHER SCIENTIFIC COM 883556102 14,167,551 -682,179 -4.59 8,368,110 -15.54 1.4409
2022-05-16 2022-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 14,167,551 -682,179 8,368,110 1.4612
2022-02-14 2021-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 14,849,730 -37,056 -0.25 9,908,317 16.50 1.5673
2021-11-15 2021-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 14,886,786 114,582 0.78 8,505,340 14.13 1.4518
2021-08-16 2021-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 14,772,204 -1,966,990 -11.75 7,452,168 -2.45 1.2665
2021-05-14 2021-03-31 13F THERMO FISHER SCIENTIFIC COM 883556102 16,739,194 757,674 4.74 7,639,398 2.63 1.4119
2021-02-12 2020-12-31 13F THERMO FISHER SCIENTIFIC COM 883556102 15,981,520 -41,513 -0.26 7,443,849 5.22 1.4344
2020-11-13 2020-09-30 13F THERMO FISHER SCIENTIFIC COM 883556102 16,023,033 -548,434 -3.31 7,074,458 17.82 1.5483
2020-08-14 2020-06-30 13F THERMO FISHER SCIENTIFIC COM 883556102 16,571,467 -253,259 -1.51 6,004,472 25.84 1.4529
2020-05-15 2020-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 16,824,726 1,242,140 7.97 4,771,494 -5.74 1.3846
2020-02-18 2019-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 15,582,586 -39,392 -0.25 5,062,315 11.25 1.1315
2019-11-14 2019-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 15,621,978 8,880 0.06 4,550,211 -0.76 1.0959
2019-08-14 2019-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 15,613,098 76,074 0.49 4,585,255 7.82 1.0756
2019-05-15 2019-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 15,537,024 547,242 3.65 4,252,794 26.78 1.0313
2019-02-14 2018-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 14,989,782 -422,460 -2.74 3,354,563 -10.83 0.9088
2018-11-14 2018-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 15,412,242 2,482,783 19.20 3,761,820 40.46 0.9152
2018-08-14 2018-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 12,929,459 317,680 2.52 2,678,208 2.86 0.5731
2018-05-15 2018-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 12,611,779 -277,943 -2.16 2,603,828 6.39 0.5862
2018-02-14 2017-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 12,889,722 10,844 0.08 2,447,501 0.44 0.5306
2017-11-14 2017-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 12,878,878 1,119,144 9.52 2,436,684 18.76 0.5519
2017-08-14 2017-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 11,759,734 671,637 6.06 2,051,721 20.47 0.4819
2017-05-15 2017-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 11,088,097 1,266,545 12.90 1,703,132 22.90 0.4071
2017-02-15 2016-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 9,821,552 -1,187,459 -10.79 1,385,821 -20.86 0.3485
2016-11-14 2016-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 11,009,011 4,485 0.04 1,751,093 7.69 0.4554
2016-08-15 2016-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 11,004,526 872 0.01 1,626,029 4.37 0.4385
2016-05-16 2016-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 11,003,654 -354,926 -3.12 1,558,007 -3.30 0.4305
2016-02-12 2015-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 11,358,580 594,558 5.52 1,611,215 22.41 0.4507
2015-11-16 2015-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 10,764,022 938,396 9.55 1,316,225 3.24 0.3871
2015-08-14 2015-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 9,825,626 50,626 0.52 1,274,973 -2.91 0.3474
2015-05-15 2015-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 9,775,000 2,517,000 34.68 1,313,174 44.41 0.3539
2015-03-02 2014-12-31 13F/A-1 THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 7,258,000 3,230,000 80.19 909,355 85.50 0.2494
2015-02-13 2014-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 7,788,000 975,135
2014-11-14 2014-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 4,028,000 996,000 32.85 490,208 37.02 0.1377
2014-08-14 2014-06-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 3,032,000 1,340,000 79.20 357,776 75.86 0.0986
2014-05-15 2014-03-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 1,692,000 642,000 61.14 203,446 74.01 0.0580
2014-02-14 2013-12-31 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 1,050,000 0 0.00 116,918 20.84 0.0329
2013-11-14 2013-09-30 13F THERMO FISHER SCIENTIFIC COMMON STOCK 883556102 1,050,000 1,050,000 96,758 0.0294
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.