MEDIFAST, INC. joint Schedule 13G filing reports that Citadel entities and Kenneth Griffin may be deemed to beneficially own 715,910 shares of Common Stock, representing 6.5% of the class based on 11,031,693 Shares outstanding as of March 23, 2026.
The filing lists ownership by Citadel Securities LLC (712,864 shares), Citadel Securities Group LP and Citadel Securities GP LLC (each 715,910 shares), and states shared voting and dispositive power rather than sole control. The joint filing is signed May 15, 2026.
Positive
None.
Negative
None.
Insights
Large passive stake disclosed by Citadel-related entities and Kenneth Griffin.
The filing reports a 6.5% position tied to Citadel Securities entities and Mr. Griffin, with shared voting and disposition rather than sole power. The position size is calculated using March 23, 2026 outstanding shares from a proxy statement.
Implications depend on trading intent and strategy; subsequent filings or transaction reports would clarify whether this is passive ownership or part of active trading activity.
Key Figures
Reported shares (Kenneth Griffin / Citadel entities):715,910 sharesCitadel Securities LLC reported amount:712,864 sharesPercent of class:6.5%+1 more
"Citadel Securities LLC may be deemed to beneficially own 712,864 Shares."
Beneficially own means having the economic rights and risks of a security—such as the right to receive dividends, sell the shares, or profit from price changes—whether or not your name appears on the official share register. Think of it like renting a car: you use it and reap the benefits even if the title lists someone else. Investors care because beneficial ownership determines who truly controls value, must be disclosed under securities rules, and can signal potential influence or trading activity that affects a stock’s price.
shared dispositive powerregulatory
"Shared Dispositive Power 715,910.00"
Schedule 13Gregulatory
"Item 1. Name of issuer: MEDIFAST, INC. ... This is being jointly filed"
A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.
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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
MEDIFAST, INC.
(Name of Issuer)
Common Stock, par value $0.001 per share (the "Shares")
(Title of Class of Securities)
58470H101
(CUSIP Number)
03/31/2026
(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):
58470H101
1
Names of Reporting Persons
Citadel Securities GP 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
715,910.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
715,910.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
715,910.00
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)
6.5 %
12
Type of Reporting Person (See Instructions)
HC, OO
Comment for Type of Reporting Person: The percentages reported in this Schedule 13G are based upon 11,031,693 Shares outstanding as of March 23, 2026 (according to the issuer's definitive proxy statement as filed with the Securities and Exchange Commission on April 6, 2026).
SCHEDULE 13G
CUSIP Number(s):
58470H101
1
Names of Reporting Persons
Citadel Securities 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
712,864.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
712,864.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
712,864.00
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)
6.5 %
12
Type of Reporting Person (See Instructions)
BD, OO
SCHEDULE 13G
CUSIP Number(s):
58470H101
1
Names of Reporting Persons
Citadel Securities Group LP
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
715,910.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
715,910.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
715,910.00
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)
6.5 %
12
Type of Reporting Person (See Instructions)
HC, PN
SCHEDULE 13G
CUSIP Number(s):
58470H101
1
Names of Reporting Persons
Citadel Advisors 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
0.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
0.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
0.00
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)
0.0 %
12
Type of Reporting Person (See Instructions)
IA, HC, OO
SCHEDULE 13G
CUSIP Number(s):
58470H101
1
Names of Reporting Persons
Citadel Advisors Holdings LP
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
0.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
0.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
0.00
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)
0.0 %
12
Type of Reporting Person (See Instructions)
HC, PN
SCHEDULE 13G
CUSIP Number(s):
58470H101
1
Names of Reporting Persons
Citadel GP 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
0.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
0.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
0.00
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)
0.0 %
12
Type of Reporting Person (See Instructions)
HC, OO
SCHEDULE 13G
CUSIP Number(s):
58470H101
1
Names of Reporting Persons
Kenneth Griffin
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
715,910.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
715,910.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
715,910.00
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)
6.5 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
MEDIFAST, INC.
(b)
Address of issuer's principal executive offices:
1501 S. Clinton Street, Suite 500, Baltimore, MD 21224
Item 2.
(a)
Name of person filing:
This Schedule 13G is being jointly filed by Citadel Securities GP LLC ("CSGP"), Citadel Securities LLC ("Citadel Securities"), Citadel Securities Group LP ("CALC4"), Citadel Advisors LLC ("Citadel Advisors"), Citadel Advisors Holdings LP ("CAH"), Citadel GP LLC ("CGP"), and Mr. Kenneth Griffin (collectively with CSGP, Citadel Securities, CALC4, Citadel Advisors, CAH, and CGP, the "Reporting Persons") with respect to the Shares of the above-named issuer owned by Citadel Securities and Citadel Securities Principal Strategies LLC, a Delaware limited liability company ("CSP"). Such owned Shares may include other instruments exercisable for or convertible into Shares.
CALC4 is the non-member manager of Citadel Securities and CSP. CSGP is the general partner of CALC4. CAH is the sole member of Citadel Advisors. CGP is the general partner of CAH. Mr. Griffin is the President and Chief Executive Officer of CGP, and owns a controlling interest in CGP and CSGP.
The filing of this statement shall not be construed as an admission that any of the Reporting Persons is the beneficial owner of any securities covered by the statement other than the securities actually owned by such person (if any).
(b)
Address or principal business office or, if none, residence:
The address of each of the Reporting Persons is 830 Brickell Plaza, Miami, Florida 33131.
(c)
Citizenship:
Each of CSGP, Citadel Securities, Citadel Advisors, and CGP is organized as a limited liability company under the laws of the State of Delaware. Each of CALC4 and CAH is organized as a limited partnership under the laws of the State of Delaware. Mr. Griffin is a U.S. citizen.
(d)
Title of class of securities:
Common Stock, par value $0.001 per share (the "Shares")
(e)
CUSIP Number(s):
58470H101
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:
1. Citadel Securities LLC may be deemed to beneficially own 712,864 Shares.
2. Each of Citadel Securities Group LP and Citadel Securities GP LLC may be deemed to beneficially own 715,910 Shares.
3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC may be deemed to beneficially own 0 Shares
4. Mr. Griffin may be deemed to beneficially own 715,910 Shares.
(b)
Percent of class:
1. The number of Shares that Citadel Securities LLC may be deemed to beneficially own constitutes 6.5% of the Shares outstanding.
2. The number of Shares that each of Citadel Securities Group LP and Citadel Securities GP LLC may be deemed to beneficially own constitutes 6.5% of the Shares outstanding.
3. The number of Shares that each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC may be deemed to beneficially own constitutes 0.0% of the Shares outstanding.
4. The number of Shares that Mr. Griffin may be deemed to beneficially own constitutes 6.5% of the Shares outstanding.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
1. Citadel Securities LLC: 0
2. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 0
3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0
4. Mr. Griffin: 0
(ii) Shared power to vote or to direct the vote:
1. Citadel Securities LLC: 712,864
2. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 715,910
3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0
4. Mr. Griffin: 715,910
(iii) Sole power to dispose or to direct the disposition of:
1. Citadel Securities LLC: 0
2. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 0
3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0
4. Mr. Griffin: 0
(iv) Shared power to dispose or to direct the disposition of:
1. Citadel Securities LLC: 712,864
2. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 715,910
3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0
4. Mr. Griffin: 715,910
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.
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.
Citadel Securities GP LLC
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
05/15/2026
Citadel Securities LLC
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
05/15/2026
Citadel Securities Group LP
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
05/15/2026
Citadel Advisors LLC
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
05/15/2026
Citadel Advisors Holdings LP
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
05/15/2026
Citadel GP LLC
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
05/15/2026
Kenneth Griffin
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, attorney-in-fact*
Date:
05/15/2026
Comments accompanying signature: * Seth Levy is signing on behalf of Kenneth Griffin as attorney-in-fact pursuant to a power of attorney previously filed with the Securities and Exchange Commission, and hereby incorporated by reference herein. The power of attorney was filed as an attachment to a filing by Citadel Advisors LLC on Schedule 13G for Allakos Inc. on October 13, 2023.
The joint filing reports 715,910 shares representing 6.5% of MEDIFAST based on 11,031,693 shares outstanding as of March 23, 2026. The shares are held across Citadel entities and Kenneth Griffin with shared voting/dispositive power.
Which Citadel entities are named in the MED Schedule 13G?
The filing names Citadel Securities LLC, Citadel Securities Group LP, Citadel Securities GP LLC, Citadel Advisors LLC, Citadel Advisors Holdings LP, and Citadel GP LLC, plus Kenneth Griffin as a reporting person.
Does the Schedule 13G show sole voting control of MED shares?
No. The filing shows 0 shares with sole voting power and reports shared voting and dispositive power for the reported share amounts, indicating shared control among the reporting persons.
What outstanding share count does the MED filing use to compute percentage?
The percentages are based on 11,031,693 Shares outstanding as of March 23, 2026, cited from the issuer's definitive proxy statement filed April 6, 2026, per the filing's comment.
When was the MED joint Schedule 13G signed?
The joint Schedule 13G signatures are dated May 15, 2026, with Seth Levy signing as authorized signatory and as attorney-in-fact for Kenneth Griffin pursuant to a previously filed power of attorney.
