Driehaus reports 4.87% stake in Xenon

Xenon Pharmaceuticals Inc. reports that Driehaus Capital Management LLC beneficially owned 4,491,653 shares of common stock, representing 4.87% of the class as of 12/31/2025.

Rhea-AI Filing Summary

Xenon Pharmaceuticals Inc. reports that Driehaus Capital Management LLC beneficially owned 4,491,653 shares of common stock, representing 4.87% of the class as of 12/31/2025. The amendment is signed by the filer’s General Counsel on 05/15/2026.

The filing lists shared voting and dispositive power for the entire position and classifies the holding as ownership of 5 percent or less of the class.

Insights

Institutional Ownership Analyst

Driehaus holds a stake just under 5% of Xenon, disclosed via an amended Schedule 13G.

The filing shows 4,491,653 shares and 4.87% ownership as of 12/31/2025, with shared voting and dispositive power. This indicates passive institutional ownership reported under beneficial-ownership rules.

Impact depends on future filings or changes in position; subsequent amendments or Schedule 13D triggers would alter the picture.

Key Figures

Filing type: Schedule 13G/A Shares beneficially owned: 4,491,653 shares Percent of class: 4.87% +2 more

5 metrics

Filing type Schedule 13G/A Amendment No. 3

Shares beneficially owned 4,491,653 shares Amount beneficially owned as of <date>12/31/2025</date>

Percent of class 4.87% Percent of class as of <date>12/31/2025</date>

Voting power Shared voting power 4,491,653 Reported in Item 4 of the Schedule 13G/A

Dispositive power Shared dispositive power 4,491,653 Reported in Item 4 of the Schedule 13G/A

Key Terms

Schedule 13G/A, Beneficially owned, Shared Dispositive Power

3 terms

Schedule 13G/A regulatory

"Amendment No. 3 and the form heading"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

Beneficially owned regulatory

"Item 4. | Ownership (a) | Amount beneficially owned: 4491653"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

Shared Dispositive Power regulatory

"Item 4. | (iv) Shared power to dispose or to direct the disposition of: 4491653"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake does Driehaus Capital report in Xenon (XENE)?

Driehaus reports beneficial ownership of 4,491,653 shares representing 4.87% of the class. The filing states this position was recorded as of 12/31/2025 and amended with a signature dated 05/15/2026.

Does the Schedule 13G/A indicate voting or disposition control?

Yes: it lists shared voting power and shared dispositive power of 4,491,653 shares. The filer reports no sole voting or sole dispositive power over the shares in the filing.

Is this filing a passive ownership disclosure or an active intent filing?

This Schedule 13G/A characterizes the position as passive beneficial ownership. The form type and the ownership percentage (4.87%) indicate a passive investor disclosure rather than an activist Schedule 13D filing.

What date is the ownership figure tied to in the filing?

The ownership figures are stated as of 12/31/2025. The amendment is signed on 05/15/2026, which amends prior Schedule 13G disclosures to reflect that reporting date.

Who signed the amendment for Driehaus Capital?

The amendment is signed by Janet McWilliams, listed as General Counsel, with the signature date of 05/15/2026 on the Schedule 13G/A.

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

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Accepted by SEC EDGAR 05/15/2026 - 07:06 AM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 3)

Xenon Pharmaceuticals Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

98420N105

(CUSIP Number)

12/31/2025

(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): 98420N105

1

Names of Reporting Persons

DRIEHAUS 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

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 4,491,653.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 4,491,653.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,491,653.00

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)

4.87 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Xenon Pharmaceuticals Inc.
(b)	Address of issuer's principal executive offices: 200-3650 Gilmore Way, Burnaby, British Columbia, Canada V56 4W8
Item 2.
(a)	Name of person filing: Driehaus Capital Management LLC
(b)	Address or principal business office or, if none, residence: 25 East Erie Street Chicago, IL 60611
(c)	Citizenship: USA
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 98420N105
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: 4491653
(b)	Percent of class: 4.87 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 4491653
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 4491653
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
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.
	Not Applicable
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.

DRIEHAUS CAPITAL MANAGEMENT LLC

Signature:	Janet McWilliams
Name/Title:	General Counsel
Date:	05/15/2026