10K-share sale by AC Immune (ACIU) CEO Andrea Pfeifer disclosed

Rhea-AI Filing Summary

AC Immune SA Chief Executive Officer Andrea Pfeifer reported an open-market sale of 10,000 common shares. The trade occurred on May 15, 2026 at a weighted average price of $2.7935 per share, with individual prices ranging from $2.75 to $2.825.

After this sale, Pfeifer directly holds 3,820,288 common shares, which include 1,921,005 common shares underlying outstanding restricted share units. She also reports 14,000 common shares held indirectly by her spouse.

Insider Trade Summary 10b5-1

Net Seller: 10,000 shares ($27,935)

Net Sell 2 txns

Insider Pfeifer Andrea

Role Chief Executive Officer

Sold 10,000 shs ($28K)

Type	Security	Shares	Price	Value
Sale	Common Share	10,000	$2.7935	$28K
holding	Common Share	--	--	--

Holdings After Transaction: Common Share — 3,820,288 shares (Direct, null); Common Share — 14,000 shares (Indirect, By spouse)

Footnotes (1)

1. The price is a weighted average price. These shares were sold in multiple transactions at prices ranging from $2.75 to $2.825. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. Includes 1,921,005 common shares underlying outstanding restricted share units.

Key Figures

Shares sold: 10,000 shares Weighted average sale price: $2.7935 per share Post-transaction direct holdings: 3,820,288 shares +3 more

6 metrics

Shares sold 10,000 shares Open-market sale on May 15, 2026

Weighted average sale price $2.7935 per share Common shares sold on May 15, 2026

Post-transaction direct holdings 3,820,288 shares Common shares held directly after sale

RSU-linked shares 1,921,005 shares Common shares underlying outstanding restricted share units

Indirect holdings by spouse 14,000 shares Common shares held indirectly through spouse

Sale price range $2.75–$2.825 per share Range of individual trade prices for the sale

Key Terms

weighted average price, restricted share units, open-market sale, indirect ownership

4 terms

weighted average price financial

"The price is a weighted average price. These shares were sold in multiple transactions at prices ranging from $2.75 to $2.825."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

restricted share units financial

"Includes 1,921,005 common shares underlying outstanding restricted share units."

Restricted share units (RSUs) are a promise from a company to give an employee or service provider actual shares or cash equal to the shares after certain conditions are met, typically staying with the company for a set time or hitting performance targets. Think of them like a time-locked gift card that becomes usable only after you’ve earned it. For investors, RSUs matter because they align employee incentives with company performance and can increase the number of shares outstanding over time, diluting existing ownership and affecting earnings per share.

open-market sale financial

"transaction_action: open-market sale"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

indirect ownership financial

"Common Share holding of 14,000.0000 shares reported as indirect with nature of ownership: By spouse."

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Pfeifer Andrea

(Last) (First) (Middle)

C/O AC IMMUNE SA

EPFL INNOVATION PARK BUILDING B

(Street)

LAUSANNE 1015

(City) (State) (Zip)

SWITZERLAND

(Country)

2. Issuer Name and Ticker or Trading Symbol
AC Immune SA [ ACIU ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Executive Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/15/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Share	05/15/2026		S		10,000	D	$2.7935(1)	3,820,288(2)	D
Common Share								14,000	I	By spouse

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. The price is a weighted average price. These shares were sold in multiple transactions at prices ranging from $2.75 to $2.825. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

2. Includes 1,921,005 common shares underlying outstanding restricted share units.

	Matthias Maurer as Attorney-in-Fact for Andrea Pfeifer	05/18/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did AC Immune (ACIU) CEO Andrea Pfeifer report?

AC Immune CEO Andrea Pfeifer reported selling 10,000 common shares in an open-market transaction. The sale occurred on May 15, 2026 at a weighted average price of $2.7935 per share, with individual trade prices ranging from $2.75 to $2.825.

At what price did Andrea Pfeifer sell AC Immune (ACIU) shares?

Andrea Pfeifer sold 10,000 AC Immune common shares at a weighted average price of $2.7935 per share. According to the filing, the individual trades were executed within a price range from $2.75 to $2.825 per share during the same trading day.

How many AC Immune (ACIU) shares does Andrea Pfeifer hold after the sale?

Following the reported sale, Andrea Pfeifer directly holds 3,820,288 AC Immune common shares. This direct position includes 1,921,005 common shares underlying outstanding restricted share units, providing a mix of currently held stock and stock-based compensation tied to future vesting.

What indirect AC Immune (ACIU) share ownership is reported for Andrea Pfeifer?

The filing shows Andrea Pfeifer with indirect ownership of 14,000 AC Immune common shares held by her spouse. This indirect position is reported separately from her 3,820,288 directly held shares, reflecting additional exposure to the company through a related party.

Do Andrea Pfeifer’s AC Immune (ACIU) holdings include restricted share units?

Yes. The filing states that 1,921,005 of Andrea Pfeifer’s directly reported AC Immune common shares are underlying outstanding restricted share units. These RSU-linked shares represent stock-based compensation that typically vests over time according to specified service or performance conditions.