Boston Scientific Corporation
MX ˙ BMV ˙ FR0010424135
SecurityMX:BSX / Boston Scientific Corporation
InstitutionMarex Group plc
Latest Disclosed Ownership6,310 shares
Latest Disclosed Value $ 395,953
Marex Group plc reports 6.53% increase in ownership of BSX / Boston Scientific Corporation

On May 13, 2026 - Marex Group plc filed a 13F-HR form disclosing ownership of 6,310 shares of Boston Scientific Corporation (MX:BSX) valued at $395,953 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 5,923 shares of Boston Scientific Corporation. This represents a change in shares of 6.53% 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 BOSTON SCIENTIFIC COM 101137107 6,310 387 6.53 396 -29.96 0.0016
2026-02-12 2025-12-31 13F BOSTON SCIENTIFIC COM 101137107 5,923 1,116 23.22 565 20.26 0.0036
2025-11-14 2025-09-30 13F BOSTON SCIENTIFIC COM 101137107 4,807 4,807 469 0.0033
2025-08-19 2025-06-30 13F BOSTON SCIENTIFIC COM 101137107 0 -4,371 -100.00 0 -100.00
2026-04-02 2025-03-31 13F BOSTON SCIENTIFIC COM 101137107 4,371 -690 -13.63 441 -2.65 0.0084
2026-04-02 2024-12-31 13F BOSTON SCIENTIFIC COM 101137107 5,061 1,559 44.52 452 54.27 0.0077
2026-04-07 2024-09-30 13F BOSTON SCIENTIFIC COM 101137107 3,502 0 0.00 293 8.92 0.0067
2026-04-02 2024-06-30 13F BOSTON SCIENTIFIC COM 101137107 3,502 -500 -12.49 270 -1.82 0.0072
2026-04-02 2024-03-31 13F BOSTON SCIENTIFIC COM 101137107 4,002 -170 -4.07 274 13.69 0.0089
2026-04-02 2023-12-31 13F BOSTON SCIENTIFIC COM 101137107 4,172 4,172 241 0.0095
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.