Rambus CEO sells 5,426 shares, receives RSU grant

Rambus Inc. President and CEO Luc Seraphin reported equity compensation activity and a modest share sale.

Accepted by SEC EDGAR 04/03/2026 - 08:15 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Rambus Inc. President and CEO Luc Seraphin reported equity compensation activity and a modest share sale. On April 1, 2026, he received 32,684 shares of Common Stock as a grant, represented by restricted stock units that vest in four equal annual installments beginning on April 1, 2027.

Also on April 1, 12,561 shares were withheld at $89.95 per share to cover his tax liability related to RSU vesting. On April 2, 2026, he executed open-market sales totaling 5,426 shares of Common Stock at weighted average prices of $86.0396, $87.1145, and $88.3501, under a pre-arranged Rule 10b5-1 trading plan. Following these transactions, he directly holds 345,767 shares of Rambus Common Stock.

Insights

Equity compensation and insider-trading analyst

CEO received RSU grant, had tax withholding, and sold a small block under a 10b5-1 plan.

Luc Seraphin, President and CEO of Rambus, was granted 32,684 shares of Common Stock via RSUs that vest annually starting on April 1, 2027. This continues his equity-based compensation, aligning part of his pay with future share performance.

To cover taxes on RSU vesting, 12,561 shares were withheld at $89.95 per share, a standard non-market mechanism. The Form 4 also shows open-market sales of 5,426 shares on April 2, 2026 at weighted average prices around the high-$80s, executed under a pre-arranged Rule 10b5-1 trading plan.

After these transactions, Seraphin directly owns 345,767 shares of Common Stock. Given the continued sizeable holding and the pre-planned nature of the sales, the net effect appears routine rather than a major shift in insider exposure.

Insider Trade Summary 10b5-1

Net Seller: 5,426 shares

Net Sell 5 txns

Insider Seraphin Luc

Role President and CEO

Sold 5,426 shs ($470K)

Share of Position Sold 1.5%

Type	Security	Shares	Price	Value
Sale	Common Stock	2,511	$86.0396	$216K
Sale	Common Stock	2,750	$87.1145	$240K
Sale	Common Stock	165	$88.3501	$15K
Grant/Award	Common Stock	32,684	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	12,561	$89.95	$1.13M

Holdings After Transaction: Common Stock — 345,767 shares (Direct)

Holdings Before and After: Common Stock, 331,070 to 345,767 shares (Direct)

Other Insiders: 1 other insider reported open-market sales of this stock in the 30 days up to this filing.

Footnotes (6)

1. F1. The shares are represented by RSUs which vest in four equal annual installments beginning on April 1, 2027 or the first business trading day thereafter. Each RSU represents a contingent right to receive one share of RMBS common stock.
2. F2. The shares were withheld to cover the Reporting Person's tax liability in connection with the vesting of restricted stock units, or RSUs.
3. F3. The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted on November 11, 2025
4. F4. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $85.70 to $86.48, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price.
5. F5. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $86.81 to $87.80, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price.
6. F6. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $87.85 to $88.71, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price.

Key Figures

RSU grant: 32,684 shares Tax withholding shares: 12,561 shares Shares sold: 5,426 shares +4 more

7 metrics

RSU grant 32,684 shares Common Stock grant represented by RSUs on April 1, 2026

Tax withholding shares 12,561 shares Withheld at $89.95/share to cover RSU-related tax liability

Shares sold 5,426 shares Open-market sales of Common Stock on April 2, 2026

Sale price tranche 1 $86.0396 per share Weighted average price for 2,511 shares sold

Sale price tranche 2 $87.1145 per share Weighted average price for 2,750 shares sold

Sale price tranche 3 $88.3501 per share Weighted average price for 165 shares sold

Shares owned after 345,767 shares Direct Common Stock holdings after reported transactions

Key Terms

restricted stock units, Rule 10b5-1 trading plan, tax-withholding disposition, weighted average price, +1 more

5 terms

restricted stock units financial

"The shares are represented by RSUs which vest in four equal annual installments"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Rule 10b5-1 trading plan regulatory

"The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

tax-withholding disposition financial

"The shares were withheld to cover the Reporting Person's tax liability"

A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.

weighted average price financial

"The price reported in Column 4 is a weighted average price"

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.

grant, award, or other acquisition financial

"transaction_code_description: Grant, award, or other acquisition"

FAQ

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

What did Rambus (RMBS) CEO Luc Seraphin report in this Form 4?

Luc Seraphin reported an RSU-based stock grant, tax withholding, and a small open-market sale. He received 32,684 shares via RSUs, had 12,561 shares withheld for taxes, and sold 5,426 shares while remaining directly invested in 345,767 Rambus shares.

How many Rambus (RMBS) shares did the CEO sell and at what prices?

Luc Seraphin sold 5,426 shares of Rambus Common Stock on April 2, 2026. The shares were sold in multiple trades at weighted average prices of $86.0396, $87.1145, and $88.3501 per share, according to the detailed transaction entries and related footnotes.

What equity award did the Rambus (RMBS) CEO receive in this filing?

He received a grant of 32,684 shares of Common Stock represented by RSUs. These RSUs vest in four equal annual installments beginning on April 1, 2027, with each restricted stock unit converting into one share of Rambus common stock upon vesting.

Why were 12,561 Rambus (RMBS) shares withheld from the CEO?

12,561 shares were withheld to cover Luc Seraphin’s tax liability from RSU vesting. This tax-withholding disposition used a price of $89.95 per share and is a non-market mechanism rather than an open-market sale, as described in the Form 4 footnotes.

Were the Rambus (RMBS) CEO share sales pre-planned under Rule 10b5-1?

Yes. The filing states the April 2, 2026 sales were executed under a Rule 10b5-1 trading plan adopted on November 11, 2025. Such plans schedule trades in advance, helping separate routine portfolio management from discretionary timing decisions by insiders.

How many Rambus (RMBS) shares does the CEO own after these transactions?

Following the reported grant, tax withholding, and sales, Luc Seraphin directly owns 345,767 shares of Rambus Common Stock. This share count is disclosed in the post-transaction holdings column for the final transaction in the Form 4’s non-derivative securities table.

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

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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^*

Seraphin Luc

(Last) (First) (Middle)

C/O RAMBUS INC.

4453 NORTH FIRST STREET, SUITE 100

(Street)

SAN JOSE CALIFORNIA 95134

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
RAMBUS INC [ RMBS ]

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

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	President and CEO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/01/2026

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 Stock	04/01/2026		A		32,684(1)	A	$0	363,754	D
Common Stock	04/01/2026		F(2)		12,561	D	$89.95	351,193	D
Common Stock	04/02/2026		S(3)		2,511	D	$86.0396(4)	348,682	D
Common Stock	04/02/2026		S(3)		2,750	D	$87.1145(5)	345,932	D
Common Stock	04/02/2026		S(3)		165	D	$88.3501(6)	345,767	D

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 shares are represented by RSUs which vest in four equal annual installments beginning on April 1, 2027 or the first business trading day thereafter. Each RSU represents a contingent right to receive one share of RMBS common stock.

2. The shares were withheld to cover the Reporting Person's tax liability in connection with the vesting of restricted stock units, or RSUs.

3. The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted on November 11, 2025

4. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $85.70 to $86.48, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price.

5. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $86.81 to $87.80, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price.

6. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $87.85 to $88.71, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price.

	/s/ Brian Wu, by power of attorney	04/03/2026
	** 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)