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

SecurityTSLX / Sixth Street Specialty Lending, Inc.
InstitutionParallel Advisors, LLC
Latest Disclosed Ownership23,335 shares
Latest Disclosed Value $ 506,841
Parallel Advisors, LLC ownership in TSLX / Sixth Street Specialty Lending, Inc.

On February 11, 2026 - Parallel Advisors, LLC filed a 13F-HR form disclosing ownership of 23,335 shares of Sixth Street Specialty Lending, Inc. (US:TSLX) valued at $506,836 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 18,041 shares of Sixth Street Specialty Lending, Inc.. This represents a change in shares of 29.34% during the quarter. The current value of the position is $402,995 USD.

Parallel Advisors, LLC has a history of taking positions in derivatives of the underlying security (TSLX) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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.

TSLX / Sixth Street Specialty Lending, 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)
2026-02-11 2025-12-31 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 23,335 5,294 29.34 507 22.82 0.0093
2025-11-13 2025-09-30 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 18,041 29 0.16 412 -3.74 0.0076
2025-07-08 2025-06-30 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 18,012 -2,696 -13.02 429 -7.56 0.0086
2025-04-08 2025-03-31 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 20,708 848 4.27 463 9.46 0.0105
2025-02-10 2024-12-31 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 19,860 -200 -1.00 423 2.92 0.0095
2024-11-13 2024-09-30 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 20,060 -1,368 -6.38 412 -10.07 0.0097
2024-08-08 2024-06-30 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 21,428 -660 -2.99 457 -3.38 0.0117
2024-05-06 2024-03-31 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 22,088 -456 -2.02 473 -2.67 0.0128
2024-02-12 2023-12-31 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 22,544 168 0.75 487 6.35 0.0144
2024-05-20 2023-09-30 13F/A-1 SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 22,376 258 1.17 457 10.65 0.0152
2023-11-14 2023-09-30 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 22,376 258 457 0.0152
2024-05-20 2023-06-30 13F/A-1 SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 22,118 8,347 60.61 413 63.89 0.0133
2023-08-04 2023-06-30 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 22,118 8,347 413 0.0133
2024-05-20 2023-03-31 13F/A-1 SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 13,771 -1,044 -7.05 252 -4.18 0.0085
2023-04-25 2023-03-31 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 13,771 -1,044 252 0.0085
2023-02-06 2022-12-31 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 14,815 14,693 12,043.44 264 13,050.00 0.0114
2022-11-10 2022-09-30 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 122 -3 -2.40 2 0.00 0.0001
2022-08-01 2022-06-30 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 125 -130 -50.98 2 -66.67 0.0001
2022-04-28 2022-03-31 13F SIXTH STREET SPECIALTY LENDING COM CEF 83012A109 255 27 11.84 6 20.00 0.0002
2022-01-20 2021-12-31 13F SIXTH STREET SPECIALTY LENDNIN COM CEF 83012A109 228 170 293.10 5 400.00 0.0002
2021-11-02 2021-09-30 13F/A-1 SIXTH STREET SPECIALTY LENDNIN COM CEF 83012A109 58 22 61.11 1 0.00 0.0000
2021-08-06 2021-06-30 13F SIXTH STREET SPECIALTY LENDNIN COM CEF 83012A109 36 -73 -66.97 1 -50.00 0.0000
2021-04-23 2021-03-31 13F SIXTH STREET SPECIALTY LENDNIN COM CEF 83012A109 109 109 2 0.0001
Disclosed Call 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
(%)
2022-01-19 2021-12-31 13F SIXTH STREET SPECIALTY LENDNIN COM CEF Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-10-22 2021-09-30 13F SIXTH STREET SPECIALTY LENDNIN COM CEF Call 36 1 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.