v3.25.2
N-2 - $ / shares
6 Months Ended 12 Months Ended
May 31, 2025
Nov. 30, 2024
Nov. 30, 2023
Nov. 30, 2022
Nov. 30, 2021
Nov. 30, 2020
Nov. 30, 2019
Cover [Abstract]              
Entity Central Index Key 0001704299            
Amendment Flag false            
Entity Inv Company Type N-2            
Document Type N-CSRS            
Entity Registrant Name Tortoise Sustainable and Social Impact Term Fund            
Financial Highlights [Abstract]              
Senior Securities [Table Text Block]

9. Senior Notes

TYG has issued private senior notes (collectively, the “Notes”), which are unsecured obligations and, upon liquidation, dissolution or winding up of a Fund, will rank: (1) senior to all of the Fund’s outstanding preferred shares, if any; (2) senior to all of the Fund’s outstanding common shares; (3) on parity with any unsecured creditors of the Fund and any unsecured senior securities representing indebtedness of the Fund and (4) junior to any secured creditors of the Fund. Holders of the Notes are entitled to receive periodic cash interest payments until maturity. The Notes are not listed on any exchange or automated quotation system.

The Notes are redeemable in certain circumstances at the option of a Fund, subject to payment of any applicable make-whole amounts or early redemption premiums. The Notes for a Fund are also subject to a mandatory redemption if the Fund fails to meet asset coverage ratios required under the 1940 Act or the rating agency guidelines if such failure is not waived or cured. At May 31, 2025, TYG was in compliance with asset coverage covenants and basic maintenance covenants for its senior notes.

Details of each Fund’s outstanding Notes, including estimated fair value, as of May 31, 2025 are included below. The estimated fair value of each series of fixed-rate Notes was calculated, for disclosure purposes, by discounting future cash flows by a rate equal to the current U.S. Treasury rate with an equivalent maturity date, plus either 1) the spread between the interest rate on recently issued debt and the U.S. Treasury rate with a similar maturity date or 2) if there has not been a recent debt issuance, the spread between the AAA corporate finance debt rate and the U.S. Treasury rate with an equivalent maturity date plus the spread between the fixed rates of the Notes and the AAA corporate finance debt rate. The estimated fair value of floating rate Notes approximates the carrying amount because the interest rate fluctuates with changes in interest rates available in the current market. The estimated fair values in the following tables are Level 2 valuations within the fair value hierarchy.

TYG:

                   

Series

 

Maturity Date

 

Interest Rate

 

Payment Frequency

 

Notional Amount

 

Estimated
Fair Value

Series AA

 

June 14, 2025

 

3.48%

 

Semi-Annual

 

$

3,226,667

 

$

3,276,154

Series NN

 

June 14, 2025

 

3.20%

 

Semi-Annual

 

 

9,680,000

 

 

9,813,809

Series KK

 

December 18, 2025

 

3.53%

 

Semi-Annual

 

 

3,226,667

 

 

3,246,477

Series OO

 

April 9, 2026

 

3.27%

 

Semi-Annual

 

 

9,680,000

 

 

9,556,010

Series PP

 

September 25, 2027

 

3.33%

 

Semi-Annual

 

 

8,066,667

 

 

7,834,720

Series QQ

 

December 17, 2028

 

2.50%

 

Semi-Annual

 

 

10,000,000

 

 

9,979,640

Series RR

 

December 18, 2031

 

5.83%

 

Semi-Annual

 

 

25,000,000

 

 

26,631,422

Series SS

 

October 16, 2025

 

3.97%

 

Semi-Annual

 

 

2,234,291

 

 

2,233,137

Series TT

 

October 16, 2026

 

4.02%

 

Semi-Annual

 

 

1,936,386

 

 

1,919,163

Series UU

 

December 17, 2028

 

2.50%

 

Semi-Annual

 

 

25,000,000

 

 

23,340,268

               

$

98,050,678

 

$

97,830,800

On December 18, 2024, TYG issued $25,000,000 Series RR Senior Notes which carry a fixed rate interest rate of 5.83% and mature on December 18, 2031.

On December 19, 2024, TYG Series L Notes, with a notional amount of $6,453,333 and a fixed interest rate of 3.99% were paid in full at maturity.

On December 20, 2024, in connection with the merger with NTG, TYG assumed NTG’s outstanding Senior Notes, with an aggregate notional amount of $29,170,677, represented as TYG Senior Notes Series RR, TT and UU.

           
Senior Securities, Note [Text Block]

9. Senior Notes

TYG has issued private senior notes (collectively, the “Notes”), which are unsecured obligations and, upon liquidation, dissolution or winding up of a Fund, will rank: (1) senior to all of the Fund’s outstanding preferred shares, if any; (2) senior to all of the Fund’s outstanding common shares; (3) on parity with any unsecured creditors of the Fund and any unsecured senior securities representing indebtedness of the Fund and (4) junior to any secured creditors of the Fund. Holders of the Notes are entitled to receive periodic cash interest payments until maturity. The Notes are not listed on any exchange or automated quotation system.

The Notes are redeemable in certain circumstances at the option of a Fund, subject to payment of any applicable make-whole amounts or early redemption premiums. The Notes for a Fund are also subject to a mandatory redemption if the Fund fails to meet asset coverage ratios required under the 1940 Act or the rating agency guidelines if such failure is not waived or cured. At May 31, 2025, TYG was in compliance with asset coverage covenants and basic maintenance covenants for its senior notes.

Details of each Fund’s outstanding Notes, including estimated fair value, as of May 31, 2025 are included below. The estimated fair value of each series of fixed-rate Notes was calculated, for disclosure purposes, by discounting future cash flows by a rate equal to the current U.S. Treasury rate with an equivalent maturity date, plus either 1) the spread between the interest rate on recently issued debt and the U.S. Treasury rate with a similar maturity date or 2) if there has not been a recent debt issuance, the spread between the AAA corporate finance debt rate and the U.S. Treasury rate with an equivalent maturity date plus the spread between the fixed rates of the Notes and the AAA corporate finance debt rate. The estimated fair value of floating rate Notes approximates the carrying amount because the interest rate fluctuates with changes in interest rates available in the current market. The estimated fair values in the following tables are Level 2 valuations within the fair value hierarchy.

TYG:

                   

Series

 

Maturity Date

 

Interest Rate

 

Payment Frequency

 

Notional Amount

 

Estimated
Fair Value

Series AA

 

June 14, 2025

 

3.48%

 

Semi-Annual

 

$

3,226,667

 

$

3,276,154

Series NN

 

June 14, 2025

 

3.20%

 

Semi-Annual

 

 

9,680,000

 

 

9,813,809

Series KK

 

December 18, 2025

 

3.53%

 

Semi-Annual

 

 

3,226,667

 

 

3,246,477

Series OO

 

April 9, 2026

 

3.27%

 

Semi-Annual

 

 

9,680,000

 

 

9,556,010

Series PP

 

September 25, 2027

 

3.33%

 

Semi-Annual

 

 

8,066,667

 

 

7,834,720

Series QQ

 

December 17, 2028

 

2.50%

 

Semi-Annual

 

 

10,000,000

 

 

9,979,640

Series RR

 

December 18, 2031

 

5.83%

 

Semi-Annual

 

 

25,000,000

 

 

26,631,422

Series SS

 

October 16, 2025

 

3.97%

 

Semi-Annual

 

 

2,234,291

 

 

2,233,137

Series TT

 

October 16, 2026

 

4.02%

 

Semi-Annual

 

 

1,936,386

 

 

1,919,163

Series UU

 

December 17, 2028

 

2.50%

 

Semi-Annual

 

 

25,000,000

 

 

23,340,268

               

$

98,050,678

 

$

97,830,800

On December 18, 2024, TYG issued $25,000,000 Series RR Senior Notes which carry a fixed rate interest rate of 5.83% and mature on December 18, 2031.

On December 19, 2024, TYG Series L Notes, with a notional amount of $6,453,333 and a fixed interest rate of 3.99% were paid in full at maturity.

On December 20, 2024, in connection with the merger with NTG, TYG assumed NTG’s outstanding Senior Notes, with an aggregate notional amount of $29,170,677, represented as TYG Senior Notes Series RR, TT and UU.

           
General Description of Registrant [Abstract]              
Investment Objectives and Practices [Text Block]

1. General Organization

This report covers the following companies, each of which is listed on the New York Stock Exchange (“NYSE”): Tortoise Energy Infrastructure Corp. (“TYG”), and Tortoise Sustainable and Social Impact Term Fund (“TEAF”). These companies are individually referred to as a “Fund” or by their respective NYSE symbols, or collectively as the “Funds”, and each is a non-diversified, closed-end management investment company under the Investment Company Act of 1940, as amended (the “1940 Act”). Each TYG and TEAF has a primary investment objective to seek a high level of total return with an emphasis on current distributions.

           
Risk Factors [Table Text Block]

3. Risks and Uncertainties

TYG concentrates its investments in the energy sector. TEAF concentrates its investments in issuers operating in essential asset sectors. Funds that primarily invest in a particular sector may experience greater volatility than companies investing in a broad range of industry sectors. A Fund may, for defensive purposes, temporarily invest all or a significant portion of its assets in investment grade securities, short-term debt securities and cash or cash equivalents. To the extent a Fund uses this strategy, it may not achieve its investment objective.

           
Effects of Leverage [Text Block]

Leverage

The fund’s leverage utilization decreased $0.1 million during the six months ended Q2 2025, as compared to six months ended Q4 2024. The fund utilizes all floating rate leverage that had a weighted-average annual rate of 5.41% and represented 15.0% of total assets as of May 31, 2025. During the period, the fund maintained compliance with its applicable coverage ratios. The interest rate on the fund’s leverage will vary in the future along with changing floating rates.

           
Annual Dividend Payment $ (0.54) $ (1.08) $ (1.08) $ (1.05) $ (0.9) $ (1.1)  
NAV Per Share $ 13.12 $ 14.68 $ 14.84 $ 16.37 $ 17.15 $ 15.85 $ 17.6
Capital Stock, Long-Term Debt, and Other Securities [Abstract]              
Capital Stock [Table Text Block]

F. Distributions to Stockholders

Distributions to common stockholders are recorded on the ex-dividend date. The Funds may not declare or pay distributions to its common stockholders if it does not meet asset coverage ratios required under the 1940 Act or the rating agency guidelines for its debt and preferred stock following such distribution. The amount of any distributions will be determined by the Board of Directors. The character of distributions to common stockholders made during the year may differ from their ultimate characterization for federal income tax purposes.

As RICs, TYG and TEAF each intend to make cash distributions of its investment company taxable income and capital gains to common stockholders. In addition, on an annual basis, TYG and TEAF each may distribute additional capital gains in the last calendar quarter if necessary to meet minimum distribution requirements and thus avoid being subject to excise taxes. Distributions paid to stockholders in excess of investment company taxable income and net realized gains will be treated as return of capital to stockholders.

Distributions to mandatory redeemable preferred (“MRP”) stockholders are accrued daily based on applicable distribution rates for each series and paid periodically according to the terms of the agreements. The Funds may not declare or pay distributions to its preferred stockholders if it does not meet a 200% asset coverage ratio for its debt or the rating agency basic maintenance amount for the debt following such distribution. The character of distributions to preferred stockholders made during the year may differ from their ultimate characterization for federal income tax purposes.

Distributions to stockholders for the year ended November 30, 2024 were characterized as follows:

TYG

TEAF

 

Common

Preferred

 

Common

Qualified dividend income

15%

100%

 

18%

Ordinary dividend income

 

31%

Return of capital

85%

 

51%

Long-term capital gain

 

* For Federal income tax purposes, distributions of short-term capital gains are included in qualified dividend income.

           
Security Voting Rights [Text Block]

TYG has issued and outstanding MRP Stock at May 31, 2025. The MRP Stock has rights determined by the Board of Directors. Except as otherwise indicated in the Funds’ Charter or Bylaws, or as otherwise required by law, the holders of MRP Stock have voting rights equal to the holders of common stock (one vote per MRP share) and will vote together with the holders of shares of common stock as a single class except on matters affecting only the holders of preferred stock or the holders of common stock. The 1940 Act requires that the holders of any preferred stock (including MRP Stock), voting separately as a single class, have the right to elect at least two directors at all times.

           
Long Term Debt, Title [Text Block]

G. Offering and Debt Issuance Costs

Offering costs related to the issuance of common stock are charged to additional paid-in capital when the stock is issued. Debt issuance costs related to senior notes and MRP Stock are deferred and amortized over the period the debt or MRP Stock is outstanding.

There were no offering or debt issuance costs recorded during the year December 1, 2024 through May 31, 2025 for TEAF. For TYG, $262,057 in debt issuance costs were recorded for the period.

           
Other Security, Title [Text Block]

12. Derivative Financial Instruments

The Funds have adopted the disclosure provisions of FASB Accounting Standard Codification 815, Derivatives and Hedging (“ASC 815”). ASC 815 requires enhanced disclosures about the Funds’ use of and accounting for derivative instruments and the effect of derivative instruments on the Funds’ results of operations and financial position. Tabular disclosure regarding derivative fair value and gain/loss by contract type (e.g., interest rate contracts, foreign exchange contracts, credit contracts, etc.) is required and derivatives accounted for as hedging instruments under ASC 815 must be disclosed separately from those that do not qualify for hedge accounting. Even though the Funds may use derivatives in an attempt to achieve an economic hedge, the Funds’ derivatives are not accounted for as hedging instruments under ASC 815 because investment companies account for their derivatives at fair value and record any changes in fair value in current period earnings.

Forward Currency Contracts

TEAF may invest in derivative instruments for hedging or risk management purposes, and for short-term purposes such as maintaining market exposure pending investment of the proceeds of an offering or transitioning its portfolio between different asset classes. The Fund’s use of derivatives could enhance or decrease the cash available to the Fund for payment of distributions or interest, as the case may be. Derivatives can be illiquid, may disproportionately increase losses and have a potentially large negative impact on the Fund’s performance. Derivative transactions, including options on securities and securities indices and other transactions in which the Fund may engage (such as forward currency transactions, futures contracts and options thereon and total return swaps), may subject the Fund to increased risk of principal loss due to unexpected movements in stock prices, changes in stock volatility levels, interest rates and foreign currency exchange rates and imperfect correlations between the Fund’s securities holdings and indices upon which derivative transactions are based. The Fund also will be subject to credit risk with respect to the counterparties to any OTC derivatives contracts the Fund enters into.

As of May 31, 2025, TEAF held no forward currency contracts.

Interest Rate Swap Contracts

TYG may enter into interest rate swap contracts in an attempt to protect it from increasing interest expense on its leverage resulting from increasing interest rates. A decline in interest rates may result in a decline in the value of the swap contracts, which may result in a decline in the net assets of TYG. At the time the interest rate swap contracts reach their scheduled termination, there is a risk that TYG will not be able to obtain a replacement transaction, or that the terms of the replacement would not be as favorable as on the expiring transaction.

In addition, if TYG is required to terminate any swap contract early due to a decline in net assets below a threshold amount or failing to maintain a required 300% asset coverage of the liquidation value of the outstanding debt, then TYG could be required to make a payment to the extent of any net unrealized depreciation of the terminated swaps, in addition to redeeming all or some of its outstanding debt. TYG segregates a portion of its assets as collateral for the amount of any net liability of its interest rate swap contracts.

TYG may be subject to credit risk on the interest rate swap contracts if the counterparty should fail to perform under the terms of the interest rate swap contracts. The amount of credit risk is limited to the net appreciation of the interest rate swap contracts, if any, as no collateral is pledged by the counterparty. In addition, if the counterparty to the interest rate swap contracts defaults, the Fund would incur a loss in the amount of the receivable and would not receive amounts due from the counterparty to offset the interest payments on the Fund’s leverage.

As of May 31, 2025, TYG held no interest rate swap contracts.

Written Call Options

Transactions in written option contracts for TYG for the period from December 1, 2024 through May 31, 2025 are as follows:

 

TYG

   
   

Number of
Contracts

     

Premium

 

Options outstanding at November 30, 2024

 

     

$

 

Options written

 

6,572

     

 

441,848

 

Options closed*

 

     

 

 

Options exercised

 

     

 

 

Options expired

 

     

 

 

Options outstanding at May 31, 2025

 

6,572

     

$

441,848

 

The following table presents the types and fair value of derivatives by location as presented on the Statements of Assets & Liabilities at May 31, 2025:

Derivatives not accounted for
as hedging instruments under ASC 815

 

Assets/(Liabilities)

   

Location

 

Fair Value

 

TYG: Written equity call options

 

Options written, at fair value

 

$

(1,466,150

)

 

The following table presents the effect of derivatives on the Statements of Operations for the period ended May 31, 2025:

Derivatives not accounted for
as hedging instruments under ASC 815

 

Location of Gains (Losses)
on Derivatives

 

Net Realized
Gain (Loss) on
Derivatives

 

Net Unrealized
Appreciation
(Depreciation)
of Derivatives

   

TYG: Written equity call options

 

Options

 

$

 

$

(1,024,302

)

 

There were no written option contracts in TEAF during the period December 1, 2024 through May 31, 2025.

           
Outstanding Security, Authorized [Shares] 100,000,000            
Outstanding Security, Held [Shares] 17,235,671