LIE SEAN (Chief Technology Officer) sold 27.9% of their position (120K shares) of CEREBRAS SYSTEMS INC. on the open market

Open‑market sale worth $25.08M — a significant reduction. Review remaining holdings and any 10b5‑1 plan disclosures.

S · 9 sales

LIE SEAN

Filed: 9/28/2026ACC: 0001628280-26-063713

InsiderLIE SEANCIK 2132472

→

IssuerCEREBRAS SYSTEMS INC.CIK 2021728

Officer10% Owner· Chief Technology Officer

Since May 2026

-156K

Net shares

Net seller

$25.08M

Total sold

Open market trades

0B · 9S

Total transactions

240K acquired · 396K disposed

Non-Derivative Transactions11

Class A Common Stock

Direct

C · Conversion

+120K

Price / share

—

Trade value

—

% of position

34.7%

9/25/2026

345.57K→465.57K

Class A Common Stock

Direct

G · Gift

−36K

Price / share

—

Trade value

—

% of position

7.7%

9/25/2026

465.57K→429.57K

Class A Common Stock

Direct

S · Sale

−500.00

Price / share

$212.14

Trade value

$106.07K

% of position

0.1%

9/25/2026

429.57K→429.07K

Class A Common Stock

Direct

S · Sale

−9.18K

Price / share

$211.32

Trade value

$1.94M

% of position

2.1%

9/25/2026

429.07K→419.89K

Class A Common Stock

Direct

S · Sale

−30.57K

Price / share

$210.45

Trade value

$6.43M

% of position

7.3%

9/25/2026

419.89K→389.33K

Class A Common Stock

Direct

S · Sale

−29.99K

Price / share

$209.53

Trade value

$6.28M

% of position

7.7%

9/25/2026

389.33K→359.34K

Class A Common Stock

Direct

S · Sale

−21.02K

Price / share

$208.41

Trade value

$4.38M

% of position

5.9%

9/25/2026

359.34K→338.31K

Class A Common Stock

Direct

S · Sale

−6.87K

Price / share

$207.54

Trade value

$1.43M

% of position

2.0%

9/25/2026

338.31K→331.44K

Class A Common Stock

Direct

S · Sale

−13.78K

Price / share

$206.63

Trade value

$2.85M

% of position

4.2%

9/25/2026

331.44K→317.67K

Class A Common Stock

Direct

S · Sale

−5.90K

Price / share

$205.30

Trade value

$1.21M

% of position

1.9%

9/25/2026

317.67K→311.77K

Class A Common Stock

Direct

S · Sale

−2.20K

Price / share

$204.50

Trade value

$449.90K

% of position

0.7%

9/25/2026

311.77K→309.57K

Total

Net shares

−36K

Net value

-$25.08M

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Class A Common Stock Direct	9/25/2026	C · Conversion	+120K	—	—	34.7%	345.57K	465.57K
Class A Common Stock Direct	9/25/2026	G · Gift	−36K	—	—	7.7%	465.57K	429.57K
Class A Common Stock Direct	9/25/2026	S · Sale	−500.00	$212.14	$106.07K	0.1%	429.57K	429.07K
Class A Common Stock Direct	9/25/2026	S · Sale	−9.18K	$211.32	$1.94M	2.1%	429.07K	419.89K
Class A Common Stock Direct	9/25/2026	S · Sale	−30.57K	$210.45	$6.43M	7.3%	419.89K	389.33K
Class A Common Stock Direct	9/25/2026	S · Sale	−29.99K	$209.53	$6.28M	7.7%	389.33K	359.34K
Class A Common Stock Direct	9/25/2026	S · Sale	−21.02K	$208.41	$4.38M	5.9%	359.34K	338.31K
Class A Common Stock Direct	9/25/2026	S · Sale	−6.87K	$207.54	$1.43M	2.0%	338.31K	331.44K
Class A Common Stock Direct	9/25/2026	S · Sale	−13.78K	$206.63	$2.85M	4.2%	331.44K	317.67K
Class A Common Stock Direct	9/25/2026	S · Sale	−5.90K	$205.30	$1.21M	1.9%	317.67K	311.77K
Class A Common Stock Direct	9/25/2026	S · Sale	−2.20K	$204.50	$449.90K	0.7%	311.77K	309.57K
Total			−36K		-$25.08M

Derivative Transactions4

Stock Option

Direct

M · Option Exercise

Converts to

Class B Common Stock

116.88K shares

−116.88K

Strike price

5.48

Held after

172.15K

Exercisable

—

9/25/2026

Stock Option

Direct

M · Option Exercise

Converts to

Class B Common Stock

3.13K shares

−3.13K

Strike price

5.02

Held after

32.42K

Exercisable

—

9/25/2026

Class B Common Stock

Direct

M · Option Exercise

Converts to

Class A Common Stock

120K shares

+120K

Strike price

Held after

7.70M

Exercisable

—

9/25/2026

Class B Common Stock

Direct

C · Conversion

Converts to

Class A Common Stock

120K shares

−120K

Strike price

Held after

7.58M

Exercisable

—

9/25/2026

Security	Converts To	Date	Type	Shares	Strike Price	Exercisable	Held After
Stock Option Direct	Class B Common Stock116.88K shares	9/25/2026	M · Option Exercise	−116.88K	5.48	—	172.15K
Stock Option Direct	Class B Common Stock3.13K shares	9/25/2026	M · Option Exercise	−3.13K	5.02	—	32.42K
Class B Common Stock Direct	Class A Common Stock120K shares	9/25/2026	M · Option Exercise	+120K		—	7.70M
Class B Common Stock Direct	Class A Common Stock120K shares	9/25/2026	C · Conversion	−120K		—	7.58M

Non-Derivative Holdings (Post-Transaction)0

No non-derivative holdings reported

Derivative Holdings (Post-Transaction)1

Class B Common Stock

Indirect

Underlying security

Class A Common Stock

Underlying shares

180.60K

Shares owned

180.60K

Exercise price

Expiration

—

Exercise window

—

Total

Underlying

180.60K

Owned

180.60K

Security	Underlying	Exercise Price	Exercise Window	Expiration	Underlying Shares	Shares Owned
Class B Common Stock Indirect	Class A Common Stock		—	—	180.60K	180.60K
Total					180.60K	180.60K