Sixth Street Specialty Lending, Inc.
US ˙ NYSE ˙ US83012A1097

SecurityTSLX / Sixth Street Specialty Lending, Inc.
InstitutionMuzinich & Co., Inc.
Latest Disclosed Ownership1,046,996 shares
Latest Disclosed Value $ 19,243,804
Muzinich & Co., Inc. reports 5.45% increase in ownership of TSLX / Sixth Street Specialty Lending, Inc.

On April 23, 2026 - Muzinich & Co., Inc. filed a 13F-HR form disclosing ownership of 1,046,996 shares of Sixth Street Specialty Lending, Inc. (US:TSLX) valued at $19,243,786 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 21, 2026 disclosing 992,898 shares of Sixth Street Specialty Lending, Inc.. This represents a change in shares of 5.45% during the quarter. The current value of the position is $18,500,419 USD.

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)
2026-04-23 2026-03-31 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 1,046,996 54,098 5.45 19,244 -10.77 6.7311
2026-01-21 2025-12-31 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 992,898 245,940 32.93 21,566 26.30 6.7811
2025-10-20 2025-09-30 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 746,958 138,342 22.73 17,075 17.83 6.5980
2025-08-04 2025-06-30 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 608,616 158,474 35.21 14,491 43.85 6.2888
2025-05-05 2025-03-31 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 450,142 57,724 14.71 10,074 20.53 5.7206
2025-02-05 2024-12-31 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 392,418 26,008 7.10 8,359 11.11 5.2357
2024-11-06 2024-09-30 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 366,410 40,330 12.37 7,522 8.06 5.3079
2024-08-07 2024-06-30 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 326,080 14,292 4.58 6,962 3.37 5.3195
2024-05-13 2024-03-31 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 311,788 0 0.00 6,735 0.00 4.4799
2024-02-14 2023-12-31 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 311,788 600 0.19 6,735 5.88 4.4799
2023-11-13 2023-09-30 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 311,188 6,675 2.19 6,361 11.76 4.4141
2023-08-11 2023-06-30 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 304,513 0 0.00 5,691 2.14 3.8738
2023-05-11 2023-03-31 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 304,513 0 0.00 5,573 2.80 4.0499
2023-02-09 2022-12-31 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 304,513 3,074 1.02 5,420 10.03 4.0513
2022-11-14 2022-09-30 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 301,439 0 0.00 4,926 -11.66 4.2231
2022-08-12 2022-06-30 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 301,439 9,403 3.22 5,576 -18.02 3.9234
2022-05-13 2022-03-31 13F SIXTH STREET SPECIALTY LENDI COM 83012A109 292,036 2,269 0.78 6,802 0.35 3.2351
2022-02-11 2021-12-31 13F SIXTH STREET SPECIALTY LENDN COM 83012A109 289,767 -1,264 -0.43 6,778 4.86 3.9073
2021-11-12 2021-09-30 13F SIXTH STREET SPECIALTY LENDN COM 83012A109 291,031 -62,420 -17.66 6,464 -17.58 4.0580
2021-08-13 2021-06-30 13F SIXTH STREET SPECIALTY LENDN COM 83012A109 353,451 -45,249 -11.35 7,843 -6.46 4.2129
2021-05-14 2021-03-31 13F SIXTH STREET SPECIALTY LENDN COM 83012A109 398,700 -116,071 -22.55 8,385 -21.50 3.2851
2021-02-16 2020-12-31 13F SIXTH STREET SPECIALTY LENDN COM 83012A109 514,771 -22,666 -4.22 10,681 15.48 4.3942
2020-11-13 2020-09-30 13F SIXTH STREET SPECIALTY LENDN COM 83012A109 537,437 19,293 3.72 9,249 8.25 3.7300
2020-08-14 2020-06-30 13F SIXTH STREET SPECIALTY LENDN COM 83012A109 518,144 518,144 8,544 2.5678
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.