M33 Growth I LP trims Oncology Institute (NASDAQ: TOI) stake with 1.8M-share sale

Rhea-AI Filing Summary

M33 Growth I LP and related funds reduced their stake in The Oncology Institute, Inc. through open market sales and now report ownership below 5% of the company’s common stock. Between May 8 and May 14, 2026, M33 LP sold a total of 1,800,000 shares on Nasdaq at prices around $4 per share.

After these transactions, the reporting persons collectively report beneficial ownership of 5,002,656 shares of common stock, including 1,358,449 shares issuable upon exercise of warrants with a $1.1980 per share exercise price, representing 4.94% of the class based on 99,982,933 shares outstanding as of April 30, 2026. TOI M, LLC now reports no beneficial ownership following an earlier distribution of shares.

Insights

Ownership & Governance Analyst

Large holder sells 1.8M TOI shares and falls below 5% ownership.

M33 Growth I LP and affiliates disclosed open market sales totaling 1,800,000 Oncology Institute shares on Nasdaq between May 8, 2026 and May 14, 2026, at per-share prices just above $4.00. These trades are typical liquidity events for a financial sponsor.

Following the sales, the group reports beneficial ownership of 5,002,656 shares, including 1,358,449 issuable from warrants with a $1.1980 exercise price, representing 4.94% of the common stock based on 99,982,933 shares outstanding as of April 30, 2026. The filing states they ceased to be 5% holders upon completing the May 14 sale.

TOI M, LLC now reports zero beneficial ownership after a prior distribution of shares. This adjustment mainly affects which entities appear as significant shareholders in future disclosures, rather than the company’s operations. Subsequent ownership filings may show whether M33 continues to pare back or maintains its remaining position over time.

Key Figures

Shares sold: 1,800,000 shares Daily sale May 8, 2026: 347,674 shares at $4.0290 Daily sale May 14, 2026: 520,000 shares at $4.0700 +5 more

8 metrics

Shares sold 1,800,000 shares Aggregate open market sales on Nasdaq between May 8–14, 2026

Daily sale May 8, 2026 347,674 shares at $4.0290 Open market transaction on Nasdaq

Daily sale May 14, 2026 520,000 shares at $4.0700 Largest single-day sale disclosed

Beneficial ownership 5,002,656 shares Post-sale holdings including warrants

Common shares held 3,644,207 shares Held by M33 Growth I LP

Warrants position 1,358,449 shares at $1.1980 Shares issuable upon exercise of warrants

Ownership percentage 4.94% Portion of TOI common stock beneficially owned

Shares outstanding 99,982,933 shares TOI common stock outstanding as of April 30, 2026

Key Terms

beneficially owned, open market transactions, warrants, sole voting power, +2 more

6 terms

beneficially owned financial

"The Reporting Persons ceased to beneficially own five percent or more of the Common Stock"

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.

open market transactions financial

"M33 LP sold an aggregate of 1,800,000 shares in open market transactions on Nasdaq"

Open market transactions are the buying and selling of a company’s shares or other securities conducted on public exchanges or through the wider market rather than through private deals or negotiated placements. They matter to investors because these trades change supply and demand in real time—like shoppers affecting a store’s inventory—and so can move prices, signal management or investor sentiment, affect liquidity, and alter ownership stakes that influence future returns and risk.

warrants financial

"1,358,449 shares issuable upon exercise of warrants to purchase shares of Common Stock for an exercise price of $1.1980 per share"

Warrants are special documents that give you the right to buy a company's stock at a set price before a certain date. They are often used as a way for companies to attract investors or raise money, and their value can increase if the company's stock price goes up.

sole voting power financial

"Number of Shares Beneficially Owned by Each Reporting Person With: 7 | Sole Voting Power 0.00"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

shared dispositive power financial

"8 | Shared Voting Power 5,002,656.00 9 | Sole Dispositive Power 0.00 10 | Shared Dispositive Power 5,002,656.00"

Schedule 13D regulatory

"This Amendment No. 6 to amends and supplements the originally filed with the SEC on November 22, 2021"

A Schedule 13D is a legal document that investors file with regulators when they buy a large enough stake in a company to potentially influence its management or decisions. It provides details about the investor’s intention, ownership stake, and plans, helping other investors understand who is gaining control and what their motives might be.

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

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Accepted by SEC EDGAR 05/15/2026 - 04:30 PM Learn about SEC filing dates

FAQ

What change in ownership did M33 Growth report in TOI stock?

M33 Growth I LP reported selling 1,800,000 Oncology Institute (TOI) shares in open market Nasdaq trades. After these sales, the reporting group beneficially owns 5,002,656 shares, including warrants, representing 4.94% of the company’s common stock based on 99,982,933 shares outstanding.

Over what period did M33 Growth sell TOI shares, and at what prices?

M33 LP sold TOI shares between May 8 and May 14, 2026, in several Nasdaq trades. Reported sale prices ranged from $4.0120 to $4.1358 per share, with individual daily volumes between 129,805 and 520,000 shares across the disclosed dates.

How many TOI shares does M33 Growth now beneficially own?

M33 Growth I LP and its related reporting persons now beneficially own 5,002,656 TOI shares. This consists of 3,644,207 common shares plus 1,358,449 shares issuable upon exercise of warrants with a $1.1980 exercise price, according to the amended Schedule 13D/A filing.

What percentage of Oncology Institute’s stock does M33 Growth hold after these sales?

After the disclosed sales, the reporting persons’ beneficial ownership is 4.94% of Oncology Institute’s common stock. This percentage is calculated using 99,982,933 shares outstanding as of April 30, 2026, plus 1,358,449 shares issuable upon exercise of their warrants.

Does TOI M, LLC still own any Oncology Institute (TOI) shares?

TOI M, LLC now reports owning no Oncology Institute shares. The filing notes that, following a previously reported distribution of common stock, TOI M, LLC no longer beneficially owns any of the issuer’s common shares, while other reporting persons continue to hold a stake.

Why did M33 Growth file Amendment No. 6 to its Schedule 13D?

Amendment No. 6 updates M33 Growth’s beneficial ownership in TOI after selling 1,800,000 shares and falling below 5%. It revises Item 3 and Item 5, restating current holdings, warrant positions, and confirming that the reporting persons ceased to be 5% holders after the May 14, 2026 sale.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 6)

Oncology Institute, Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

23343Q100

(CUSIP Number)

Gabriel Ling
c/o M33 Growth I LP, 888 Boylston Street, Suite 500
Boston, MA, 02199
6172045104

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

05/14/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 23343Q100

1

Name of reporting person

M33 Growth I L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 5,002,656.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 5,002,656.00

11

Aggregate amount beneficially owned by each reporting person

5,002,656.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

4.94 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

(1) This Schedule 13D is filed by M33 Growth I LP ("M33 LP"), M33 Growth I GP LLC ("M33 LLC") and TOI M, LLC ("TOI M" and, with M33 LP, collectively, the "Reporting Persons"). The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13D. (2) Consists of (i) 3,644,207 shares held by M33 LP and (ii) 1,358,449 shares issuable upon exercise of warrants to purchase shares of Common Stock (as defined herein) for an exercise price of $1.1980 per share ("Warrants") held by M33 LP. M33 LLC serves as the sole general partner of M33 LP and, as such, M33 LLC possesses voting and dispositive power over the shares held by M33 LP, and may be deemed to have indirect beneficial ownership of the shares held by M33 LP. (3) This percentage is calculated based upon 99,982,933 shares of the Issuer's (as defined herein) common stock outstanding as of April 30, 2026, as disclosed in the Quarterly Report on Form 10-Q for the quarter ended March 31, 2026 filed by the Issuer with the Securities and Exchange Commission (the "SEC") on May 7, 2026 and the 1,358,449 shares issuable upon exercise of the Warrants.

SCHEDULE 13D

CUSIP Number(s): 23343Q100

1

Name of reporting person

M33 Growth I GP LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 5,002,656.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 5,002,656.00

11

Aggregate amount beneficially owned by each reporting person

5,002,656.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

4.94 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

(1) This Schedule 13D is filed by the Reporting Persons. The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13D. (2) Consists of (i) 3,644,207 shares held by M33 LP and (ii) 1,358,449 shares issuable upon exercise of Warrants held by M33 LP. M33 LLC serves as the sole general partner of M33 LP and, as such, M33 LLC possesses voting and dispositive power over the shares held by M33 LP, and may be deemed to have indirect beneficial ownership of the shares held by M33 LP. (3) This percentage is calculated based upon 99,982,933 shares of the Issuer's (as defined herein) common stock outstanding as of April 30, 2026, as disclosed in the Quarterly Report on Form 10-Q for the quarter ended March 31, 2026 filed by the Issuer with the Securities and Exchange Commission (the "SEC") on May 7, 2026 and the 1,358,449 shares issuable upon exercise of the Warrants.

SCHEDULE 13D

CUSIP Number(s): 23343Q100

1

Name of reporting person

TOI M, LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.00 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

(1) This Schedule 13D is filed by the Reporting Persons, including TOI M, LLC. Following the distribution of shares of Common Stock previously reported, TOI M, LLC no longer beneficially owns any shares of the Issuer's Common Stock.

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.0001 per share
(b)	Name of Issuer: Oncology Institute, Inc.
(c)	Address of Issuer's Principal Executive Offices: 18000 Studebaker Road, Suite 800, Cerritos, CALIFORNIA , 90703.
Item 1 Comment: This Amendment No. 6 (the "Amendment") to Schedule 13D amends and supplements the Schedule 13D originally filed with the SEC on November 22, 2021, as amended by Amendment No. 1 filed with the SEC on July 12, 2022, Amendment No. 2 filed with the SEC on September 26, 2022, Amendment No. 3 filed with the SEC on March 28, 2025, Amendment No. 4 filed with the SEC on September 5, 2025 and Amendment No. 5 filed with the SEC on November 20, 2025 (as amended, the "Schedule 13D"), on behalf of M33 Growth I LP ("M33 LP"), M33 Growth I GP LLC ("M33 LLC") and TOI M, LLC ("TOI M" and, together with M33 LP and M33 LLC, collectively, the "Reporting Persons"), relates to the common stock, $0.001 par value ("Common Stock"), of The Oncology Institute, Inc., a Delaware corporation (the "Issuer" or "TOI"). The Items below amend and supplement the information disclosed under the corresponding Items of Schedule 13D as described below. Except as specifically provided herein, this Amendment does not modify any of the information previously reported in the Schedule 13D. Capitalized terms used but not defined herein shall have the meanings given to such terms in the Schedule 13D.
Item 3.	Source and Amount of Funds or Other Consideration
	Between May 8, 2026 and May 14, 2026, M33 LP sold an aggregate of 1,800,000 shares in open market transactions on Nasdaq.
Item 4.	Purpose of Transaction
	Item 4 is hereby supplemented as follows: The information set forth in Item 3 of this Schedule 13D, as amended therein, is incorporated herein by reference.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5 is hereby amended and restated as follows: (a) and (b) See Items 7-11 of the cover pages of this Statement, as amended, and Item 3 of the Schedule 13D.
(b)	Between May 8, 2026 and May 14, 2026, M33 LP sold an aggregate of 1,800,000 shares in open market transactions on Nasdaq as follows: DATE SHARES SALE PRICE May 8, 2026 347,674 $4.0290 May 11, 2026 277,521 $4.0120 May 12, 2026 129,805 $4.0181 May 13, 2026 280,000 $4.1358 May 13, 2026 245,000 $4.1113 May 14, 2026 520,000 $4.0700
(c)	No other person is known to the Reporting Persons to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the shares of Common Stock covered by this Statement.
(d)	The Reporting Persons ceased to beneficially own five percent or more of the Common Stock upon completion of the sale on May 14, 2026 described above.
Item 6.	Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer
	There are no amendments or supplements to the information previously set forth in Item 6 of the Schedule 13D.
Item 7.	Material to be Filed as Exhibits.
	There are no amendments or supplements to the information previously set forth in Item 7 of the Schedule 13D

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.

M33 Growth I L.P.

Signature:	/s/ Gabriel Ling
Name/Title:	Gabriel Ling/Managing Member
Date:	05/15/2026

M33 Growth I GP LLC

Signature:	/s/ Gabriel Ling
Name/Title:	Gabriel Ling/Managing Member
Date:	05/15/2026

TOI M, LLC

Signature:	/s/ Gabriel Ling
Name/Title:	Gabriel Ling/Managing Member
Date:	05/15/2026