Nantahala group discloses 9.69% ADC Therapeutics (ADCT) ownership in 13G filing

Rhea-AI Filing Summary

ADC Therapeutics SA is reported to have a significant shareholder group led by Nantahala Capital Management, LLC and its managing members, Wilmot B. Harkey and Daniel Mack. As of June 30, 2026, they may be deemed to beneficially own 12,326,184 common shares of ADC Therapeutics, representing 9.69% of the outstanding common shares.

All reported holdings are held through funds and separately managed accounts controlled by Nantahala. The Reporting Persons have no sole voting or dispositive power over the shares; instead, they report shared voting and shared dispositive power over the full 12,326,184 shares.

Key Figures

Beneficially owned shares: 12,326,184 shares Percent of class: 9.69% Shared voting power: 12,326,184 shares +4 more

7 metrics

Beneficially owned shares 12,326,184 shares Common shares of ADC Therapeutics SA beneficially owned as of June 30, 2026

Percent of class 9.69% Ownership percentage of ADC Therapeutics common shares for each Reporting Person as of June 30, 2026

Shared voting power 12,326,184 shares Shares over which the Reporting Persons have shared power to vote or direct the vote

Sole voting power 0 shares Shares over which each Reporting Person has sole power to vote

Shared dispositive power 12,326,184 shares Shares over which the Reporting Persons have shared power to dispose or direct disposition

Par value CHF 0.08 per share Par value of ADC Therapeutics common shares reported in the ownership filing

CUSIP H0036K147 CUSIP number for ADC Therapeutics common shares

Key Terms

beneficial owner, shared voting power, dispositive power, control person, +1 more

5 terms

beneficial owner financial

"Nantahala may be deemed to be the beneficial owner of 12,326,184 Shares"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

shared voting power financial

"Shared Voting Power 12,326,184.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

dispositive power financial

"Shared Dispositive Power 12,326,184.00"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

control person financial

"Each of Messrs. Harkey and Mack is filing this as a control person"

A control person is an individual or entity that can significantly influence a company’s decisions and direction through ownership, voting power, or contractual rights—think of them as the captain who can steer the ship. Investors care because a control person’s choices affect corporate strategy, board appointments, and transactions that can raise or lower a stock’s value, and they often carry additional legal responsibilities and disclosure requirements to protect other shareholders.

investment adviser financial

"Nantahala, an investment adviser as described in ss. 240.13d-1(b)(1)(ii)(E)"

An investment adviser is a person or firm that professionally manages money and gives recommendations about buying, selling, or holding investments. Like a financial coach or guide, they have a legal duty to act in a client's best financial interest, so their advice, fees and potential conflicts can directly affect returns and risk — making their role important for investors who want informed, accountable help with portfolios.

FAQ

What percentage of ADC Therapeutics SA (ADCT) is owned by Nantahala Capital Management?

Nantahala Capital Management and its principals may be deemed to beneficially own 9.69% of ADC Therapeutics’ common shares, based on 12,326,184 shares reported as of June 30, 2026.

How many ADC Therapeutics (ADCT) shares does Nantahala Capital Management report owning?

The reporting group led by Nantahala Capital Management reports beneficial ownership of 12,326,184 common shares of ADC Therapeutics as of June 30, 2026, held through funds and separately managed accounts.

What voting power does Nantahala have over ADC Therapeutics (ADCT) shares?

Nantahala and the individual Reporting Persons report 0 shares with sole voting power and 12,326,184 shares with shared voting power, indicating decisions are made on a shared basis for these holdings.

Do the ADC Therapeutics (ADCT) shares belong personally to Harkey and Mack?

The filing states Messrs. Harkey and Mack may be deemed beneficial owners as managing members of Nantahala, which holds 12,326,184 shares through funds and accounts under its control, rather than as direct personal holdings.

What type of security in ADC Therapeutics (ADCT) is reported in this Schedule 13G?

The Schedule 13G covers ADC Therapeutics’ Common Shares, par value CHF 0.08 per share, identified by CUSIP H0036K147, with reported beneficial ownership by Nantahala and its managing members.

What is Nantahala Capital Management’s role regarding ADC Therapeutics (ADCT) shares?

Nantahala is described as an investment adviser whose funds and separately managed accounts hold 12,326,184 ADC Therapeutics shares. Messrs. Harkey and Mack file as control persons with shared voting and dispositive power.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/14/2026 - 04:39 PM Accepted by SEC EDGAR 08/14/2026 - 04:34 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

ADC Therapeutics SA

(Name of Issuer)

Common Shares, par value CHF 0.08 per share

(Title of Class of Securities)

H0036K147

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): H0036K147

1

Names of Reporting Persons

Nantahala Capital Management, LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

MASSACHUSETTS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 12,326,184.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 12,326,184.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,326,184.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

9.69 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP Number(s): H0036K147

1

Names of Reporting Persons

Wilmot B. Harkey

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 12,326,184.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 12,326,184.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,326,184.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

9.69 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP Number(s): H0036K147

1

Names of Reporting Persons

Daniel Mack

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 12,326,184.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 12,326,184.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,326,184.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

9.69 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: ADC Therapeutics SA
(b)	Address of issuer's principal executive offices: BIOPOLE ROUTE DE LA CORNICHE 3B EPALINGES, SWITZERLAND, 1066
Item 2.
(a)	Name of person filing: (1) Nantahala Capital Management, LLC ("Nantahala") (2) Wilmot B. Harkey (3) Daniel Mack (together the "Reporting Persons")
(b)	Address or principal business office or, if none, residence: 130 Main St. 2nd Floor, New Canaan, Connecticut 06840
(c)	Citizenship: (1) Nantahala is a Massachusetts limited liability company. (2) Each of Messrs. Harkey and Mack is a citizen of the United States of America.
(d)	Title of class of securities: Common Shares, par value CHF 0.08 per share
(e)	CUSIP Number(s): H0036K147
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: As of June 30, 2026, Nantahala may be deemed to be the beneficial owner of 12,326,184 Shares held by funds and separately managed accounts under its control, and as the managing members of Nantahala, each of Messrs. Harkey and Mack may be deemed to be a beneficial owner of those Shares.
(b)	Percent of class: As of June 30, 2026, each of the Reporting Persons may be deemed to be the beneficial owner of the following percentage of the total number of Shares outstanding: (1) Nantahala Capital Management, LLC ("Nantahala") : 9.69% (2) Wilmot B. Harkey: 9.69% (3) Daniel Mack: 9.69%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: (1) Nantahala Capital Management, LLC ("Nantahala") : 0 Shares. (2) Wilmot B. Harkey: 0 Shares. (3) Daniel Mack: 0 Shares.
	(ii) Shared power to vote or to direct the vote: (1) Nantahala Capital Management, LLC ("Nantahala") : 12,326,184 Shares. (2) Wilmot B. Harkey: 12,326,184 Shares. (3) Daniel Mack: 12,326,184 Shares.
	(iii) Sole power to dispose or to direct the disposition of: (1) Nantahala Capital Management, LLC ("Nantahala") : 0 Shares. (2) Wilmot B. Harkey: 0 Shares. (3) Daniel Mack: 0 Shares.
	(iv) Shared power to dispose or to direct the disposition of: (1) Nantahala Capital Management, LLC ("Nantahala") : 12,326,184 Shares. (2) Wilmot B. Harkey: 12,326,184 Shares. (3) Daniel Mack: 12,326,184 Shares.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. Each of Messrs. Harkey and Mack is filing this Schedule 13G as a control person in respect of shares beneficially owned by Nantahala, an investment adviser as described in ss. 240.13d-1(b)(1)(ii)(E). See Item 4(a).
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Nantahala Capital Management, LLC

Signature:	/s/ Taki Vasilakis
Name/Title:	Taki Vasilakis / Chief Compliance Officer
Date:	08/14/2026

Wilmot B. Harkey

Signature:	/s/ Wilmot B. Harkey
Name/Title:	Wilmot B. Harkey
Date:	08/14/2026

Daniel Mack

Signature:	/s/ Daniel Mack
Name/Title:	Daniel Mack
Date:	08/14/2026