Comparable stake leader
RENAISSANCE TECHNOLOGIES LLC
SEC ownership of MEDIFAST INC
Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0000910329.
Disclosed value leader
BlackRock, Inc.
Comparable rows
50/50
Latest evidence
26 May 2026
- Public ticker
- MED on NYSE
- Parsed ownership sources
-
13D/G, 13F, and 3/4/5
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
- Largest SEC-reported holder
-
RENAISSANCE TECHNOLOGIES LLC
Ranking: Comparable ownership first, then disclosed value
- Comparable ownership rows
-
50 of 50
Meaning: Rows with safely comparable ownership %
- Latest 13D/G holder
-
RENAISSANCE TECHNOLOGIES LLC
Source: Latest parsed Schedule 13D/G stake
- Latest parsed ownership date
-
26 May 2026
Freshness: Most recent filing date in this holder set
- Issuer CIK
- 0000910329
- Issuer location
- Baltimore, MD
Ownership snapshot
CIK-linked ownership evidence from parsed SEC filings.
3 signals
Issuer
Names, identifiers, and filing context for this profile.
2 identity fields
Ownership snapshot
Top shareholders of MEDIFAST INC (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
RENAISSANCE TECHNOLOGIES LLC
Disclosed value leader
BlackRock, Inc.
Comparable rows
50/50
Latest evidence
26 May 2026
13D/G
13F
3/4/5
Lead comparable stake: 7%
13D/G row: RENAISSANCE TECHNOLOGIES LLC
Showing 1-8 of 50 holder rows.
Quick read
RENAISSANCE TECHNOLOGIES LLC leads the comparable SEC ownership view at 7%.
50 of 50 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens RENAISSANCE TECHNOLOGIES LLC's linked filing trail.
Comparable ownership
Top 5
RENAISSANCE TECHNOLOGIES LLC
7%
Citadel Securities GP LLC
6.5%
Steamboat Capital Partners, LLC
6%
CHARLES SCHWAB INVESTMENT MANAGEM...
5.7%
BlackRock, Inc.
2.9%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-8 of 50 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| RENAISSANCE TECHNOLOGIES LLC |
13D/G
13F
Company
|
7%
|
$8,139,429
773,710 shares
|
-$1,212,093 | 02 Jan 2026 |
| Citadel Securities GP LLC |
13D/G
|
6.5%
|
$7,531,373
715,910 shares
|
$0 | 31 Mar 2026 |
| Steamboat Capital Partners, LLC |
13F
13D/G
Company
|
6%
from 13D/G
|
$7,210,342
707,590 shares
|
— | 31 Mar 2026 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC |
13F
13D/G
Company
|
5.7%
from 13D/G
|
$6,435,382
631,539 shares
|
— | 31 Mar 2026 |
| BlackRock, Inc. |
13F
13D/G
Company
|
2.9%
from 13D/G
|
$9,623,975
944,453 shares
|
— | 31 Mar 2026 |
| SUSQUEHANNA SECURITIES, LLC |
13D/G
G1 Execution Services, LLC
|
1.4%
|
$1,741,155
148,944 shares
|
-$5,915,152 | 31 Dec 2025 |
| Parsa Kiai |
3/4/5
Director
|
6.1%
|
$7,100,357
693,910 shares
|
— | 26 May 2026 |
| Daniel R. Chard |
3/4/5
Chairman & CEO, Director
|
3.1%
|
$3,787,830
355,609 shares
|
+$178,725 | 13 Mar 2026 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
Forms 3/4/5 flow
Insider trading overview
Net insider flow leans to buying over the last 12 months. Net value: +$241,675.
Buys
$241,675
Insiders: 2
Sells
$0
Insiders: 0
Net
+$241,675
Shares: +22,678
Window
Last 12 months
4 rolling buckets
Buy value
Sell value
Shares: 22,678
Shares: 0
| Window (months) | Buy shares | Sell shares | Buy value | Sell value | Net value |
|---|---|---|---|---|---|
| 0-3 | 5,000 | 0 | $62,950 | $0 | +$62,950 |
| 3-6 | 17,678 | 0 | $178,725 | $0 | +$178,725 |
| 6-9 | 0 | 0 | $0 | $0 | $0 |
| 9-12 | 0 | 0 | $0 | $0 | $0 |
Reporting owners
Insider holders from Forms 3/4/5
Showing 1-14 of 14 reporting-owner rows connected to MEDIFAST INC. Open a relationship link for the CIK-to-CIK filing trail.
Rows
14
Largest Forms 3/4/5 holder
Parsa Kiai
Net 12M change
+$241,675
Latest report
26 May 2026
| Name | Relationship | Holdings Value | Past Year Net Change | Change % | Valuation | Report Date |
|---|---|---|---|---|---|---|
| Parsa Kiai | Director | $7,100,357 | Mixed | 26 May 2026 | ||
| Daniel R. Chard | Chairman & CEO, Director | $3,787,830 | +$178,725 | +5% | Mixed | 13 Mar 2026 |
| Kevin G. Byrnes | Director | $1,027,977 | Mixed | 11 Nov 2021 | ||
| James P. Maloney | Chief Financial Officer | $779,992 | Mixed | 13 Mar 2026 | ||
| Jeffrey J. Brown | Director | $573,487 | Mixed | 25 Jun 2025 | ||
| Ming Xian | Director | $430,393 | Mixed | 26 May 2026 | ||
| Scott Schlackman | Director | $430,310 | +$62,950 | +17% | Mixed | 26 May 2026 |
| Andrea B. Thomas | Director | $363,753 | Mixed | 26 May 2026 | ||
| Michael A. Hoer | Director | $351,575 | Mixed | 25 Jun 2025 | ||
| Elizabeth A. Geary | Director | $318,182 | Mixed | 26 May 2026 | ||
| Jonathan Barrett MacKenzie | VP, Finance & CAO | $222,549 | Mixed | 13 Mar 2026 | ||
| Nicholas Mark Johnson | President | $195,833 | Mixed | 05 Jan 2026 | ||
| Jeffrey Matthew Rose | Director | $187,689 | Mixed | 26 May 2026 | ||
| Constance J. Hallquist | Former Director | $148,251 | Mixed | 06 Oct 2023 |
Recent insider transactions for MEDIFAST INC
Showing up to 300 recent insider transactions from the last 12 months.
| Insider | Symbol | Class | Transaction | % | SEC-reported value | SEC-reported price | Shares | Shares owned | Date | Ownership |
|---|---|---|---|---|---|---|---|---|---|---|
| Jeffrey Matthew Rose | MED | Common Stock | Award | 18,419 | 18,419 | 26 May 2026 | Direct | |||
| Parsa Kiai | MED | Common Stock | Award | 19,317 | 19,317 | 26 May 2026 | Direct | |||
| Andrea B. Thomas | MED | Common Stock | Award | 48.6% | 11,680 | 35,697 | 26 May 2026 | Direct | ||
| Scott Schlackman | MED | Common Stock | Award | 38.2% | 11,680 | 42,229 | 26 May 2026 | Direct | ||
| Elizabeth A. Geary | MED | Common Stock | Award | 59.8% | 11,680 | 31,225 | 26 May 2026 | Direct | ||
| Ming Xian | MED | Restricted Stock Units (cash settled) | Award | 36.3% | 11,680 | 43,823 | 26 May 2026 | Direct | ||
| Scott Schlackman | MED | Common Stock | Purchase | 8.91% | $31,325 | $12.53 | 2,500 | 30,549 | 11 May 2026 | Direct |
| Scott Schlackman | MED | Common Stock | Purchase | 9.79% | $31,625 | $12.65 | 2,500 | 28,049 | 08 May 2026 | Direct |
| Jonathan Barrett MacKenzie | MED | Common Stock | Award | 108.2% | 10,830 | 20,838 | 25 Mar 2026 | Direct | ||
| Jonathan Barrett MacKenzie | MED | Common Stock | Tax liability | -7.93% | -862 | 10,008 | 25 Mar 2026 | Direct | ||
| James P. Maloney | MED | Common Stock | Award | 93.8% | 35,358 | 73,033 | 25 Mar 2026 | Direct | ||
| James P. Maloney | MED | Common Stock | Tax liability | -7.88% | -3,224 | 37,675 | 25 Mar 2026 | Direct | ||
| Daniel R. Chard | MED | Common Stock | Award | 28.5% | 41,795 | 188,233 | 25 Mar 2026 | Direct | ||
| Daniel R. Chard | MED | Common Stock | Tax liability | -12.1% | -20,095 | 146,438 | 25 Mar 2026 | Direct | ||
| Daniel R. Chard | MED | Common Stock | Purchase | $178,725 | $10.11 | 17,678 | 17,678 | 20 Mar 2026 | Dan and Allyson as Joint Tenants | |
| Jonathan Barrett MacKenzie | MED | Common Stock | Tax liability | -0.64% | -70 | 10,870 | 17 Mar 2026 | Direct | ||
| James P. Maloney | MED | Common Stock | Tax liability | -1.16% | -482 | 40,899 | 17 Mar 2026 | Direct | ||
| Daniel R. Chard | MED | Common Stock | Tax liability | -1.56% | -2,638 | 166,533 | 17 Mar 2026 | Direct | ||
| Jonathan Barrett MacKenzie | MED | Common Stock | Tax liability | -1.78% | -198 | 10,940 | 13 Mar 2026 | Direct | ||
| James P. Maloney | MED | Common Stock | Tax liability | -2.17% | -918 | 41,381 | 13 Mar 2026 | Direct | ||
| Daniel R. Chard | MED | Common Stock | Tax liability | -4.01% | -7,075 | 169,171 | 13 Mar 2026 | Direct |
* marks a reported price that did not pass the local price check.