Filer Snapshot

CSS LLC/IL

CIK 0001103646. SEC filing timeline plus parsed ownership intelligence from 13F, 13D/G, and Forms 3/4/5 where available.

Entity type

Company

Total filings

99

Latest filing

15 May 2026

Industry

n/a

Filing-backed research brief

Start with the SEC data that changes for this CIK

Latest signal: 13F-HR for Q1 2026. Each card links back to the PortfolioSavvy page where the filing evidence is closest.

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Largest parsed holding

Lumentum Hldgs Inc

$216.5M reported value

Open holding

13D/G large stake

MXE

31 Dec 2025 · 7.6% ownership

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Source: SEC Form 13F

13F-HR filed on 15 May 2026 for CIK 0001103646.

View Source Filing
Ownership signals 1 signal
Ownership signals

SEC value by filing type

Compare filing types separately; 13F, 13D/G, and Forms 3/4/5 are different evidence sources.

Latest 13F portfolio$1.78B

Quarterly institutional portfolio holdings.

Forms 3/4/5 positions$10.77M

Reporting-owner positions with enough data to estimate value.

Latest 13F portfolio value

$1.78B

Market value from the latest parsed Form 13F portfolio.

Estimated Forms 3/4/5 position value

$10.77M

Estimated only when owner filings include enough share and price data.

Largest 13F positions

LUMENTUM HLDGS INC, ECHOSTAR CORP, JAZZ INVESTMENTS I LTD, LIVE NATION ENTERTAINMENT IN

Largest symbols in the latest parsed 13F information table.

Largest linked SEC positions

Largest issuer positions found across parsed 13F, 13D/G, and Forms 3/4/5 data.

SWZ VINE

Largest 13F positions

Largest symbols in the latest parsed Form 13F information table.

LUMENTUM HLDGS INC ECHOSTAR CORP JAZZ INVESTMENTS I LTD LIVE NATION ENTERTAINMENT IN TRANSOCEAN INC PEABODY ENGR CORP NEEPRV CENTERPOINT ENERGY INC
+12 moreALNYLAM PHARMACEUTICALS INC RSP VOO EQUINOX GOLD CORP CORZW ALBPRA AKAMAI TECHNOLOGIES INC STRIDE INC IAU BRIDGEBIO PHARMA INC APOPRA CLOUDFLARE INC

Schedule 13G positions

Passive or institutional large-stake positions disclosed in parsed Schedule 13G filings.

CHN SWZ JEQ BMTX MXE RSF
+1 moreLBRDB
How to read these SEC values
  • Read each filing type on its own: 13F portfolios, 13D/G large stakes, and Forms 3/4/5 owner positions answer different questions.
  • Open the linked research paths when you need to verify the exact SEC filing behind a value.
Identity 1 identity field
Business address
1 North Wacker Drive, Suite 3075, Chicago, IL, 60606
SEC profile 2 profile fields
State of incorporation
IL
Fiscal year-end
31 December

Filer intelligence

What SEC filings say about CSS LLC/IL

A compact read of parsed XML filings. 13F, 13D/G, and Forms 3/4/5 are shown separately because they answer different ownership questions.

Open 13F portfolio Save filer

Quick read

  • Latest parsed 13F shows $1.78B across 739 reported holdings for Q1 2026.
  • Largest parsed 13F holding: LUMENTUM HLDGS INC at $216.5M.
  • 5 recent 13D/G stake rows found; top row is MXE at 7.6% ownership.
  • Forms 3/4/5 show insider context for SWZ worth $10.58M.

SEC source mix

Counts show available parsed rows, not one combined ownership total.

XML parsed
13F portfolio 739 rows

Quarterly institutional portfolio holdings.

Open
13D/G stakes 5 rows

Beneficial ownership and large-stake disclosures.

Open
Forms 3/4/5 4 rows

Officer, director, and 10% owner holdings or transactions.

Open

Top parsed 13F holdings

Visual share of the latest parsed 13F portfolio. Values are reported market value, not a recommendation.

Q1 2026 - 15 May 2026

Top 5 concentration

30%

Share of latest parsed 13F value represented by the visible holdings below.

Top 5 reported value

$526.38M

Compared with $1.78B total 13F value.

Top 5 net change

-$10.01M

Position-value change inside the visible top holdings only.

13F concentration map

A simple visual split of the latest parsed 13F portfolio.

Largest add: NEEPRV · Largest trim: Ionis Pharmaceuticals Inc

Lumentum Hldgs Inc Echostar Corp Jazz Investments I Ltd Live Nation Entertainment In Transocean Inc Other holdings

13D/G large-stake context

MXE

31 Dec 2025 · Common

7.6%
Issuer page 13D/G history

SWZ

30 Dec 2025 · Closed End Fund

9.9%
Issuer page 13D/G history

RSF

16 Dec 2025 · common

6.3%
Issuer page 13D/G history

CHN

31 Oct 2025 · Common

0%
Issuer page 13D/G history

Forms 3/4/5 insider context

SWZ

29 Dec 2025 · 10% owner

$10.58M
Issuer page Owner page

VINE

14 Sep 2023 · 10% owner

$189.5K
Issuer page Owner page

MIE

06 Aug 2021 · 10% owner

Issuer page Owner page

DSE

25 Jun 2021 · 10% owner

Issuer page Owner page

Latest update

What changed recently for CSS LLC/IL

New filing available

Latest 13F period: Q1 2026. Open the source-backed page to inspect the fresh filing or facts context.

Update date

15 May 2026

Page type

Filer profile

Latest period

Q1 2026

Institutional portfolio context was refreshed from a 13F filing filed on 15 May 2026.

Open filer profile Browse recent public updates

Benchmark Context

Benchmark context for this company

CSS LLC/IL has a source-backed company facts view where you can compare the latest reported metrics with its own recent history and with peer rankings for the same metric.

Compared with

Start on the facts page for period-to-period context, then open a metric ranking when you want to compare the same reported fact across other SEC-reporting companies.

Why this is notable

Latest 13F period: Q1 2026. That gives you a fresh baseline before you compare this company with peers.

  • Peer comparisons stay conservative: same metric, compatible units, latest valid company row only.
  • Open the facts page first if you want the cleanest path to verification.

Benchmark context is only shown where the app has enough comparable SEC-backed data to keep the interpretation honest.

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SEC filing record

CIK 0001103646 filing coverage

Start with this filing record, then use the linked ownership pages when parsed 13F, 13D/G, Forms 3/4/5, or facts data exists for this CIK.

SEC filings
99
First seen
14 Feb 2014
Latest filing
15 May 2026
Entity
Company

Observed form types

13F-HR 3 4 SCHEDULE 13G SCHEDULE 13G/A

CIK-linked evidence first

CSS LLC/IL SEC filings CSS LLC/IL 13F portfolio CSS LLC/IL 13D/G history CSS LLC/IL owner filings Open SEC filing index

Latest Filings

Showing the latest 12 of 99 SEC filings for CSS LLC/IL.

Open full filing history
13F-HR

13F-HR filing

Filing date
15 May 2026
Reporting date
31 Mar 2026
SEC evidence
Open document Open filing
Next action
Verify source filing
SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
17 Apr 2026
Reporting date
Not listed
SEC evidence
Open document Open filing
Next action
Verify source filing
13F-HR

13F-HR filing

Filing date
17 Feb 2026
Reporting date
31 Dec 2025
SEC evidence
Open document Open filing
Next action
Verify source filing
SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
13 Feb 2026
Reporting date
Not listed
SEC evidence
Open document Open filing
Next action
Verify source filing
SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
31 Dec 2025
Reporting date
Not listed
SEC evidence
Open document Open filing
Next action
Verify source filing
SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
19 Dec 2025
Reporting date
Not listed
SEC evidence
Open document Open filing
Next action
Verify source filing
SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
16 Dec 2025
Reporting date
Not listed
SEC evidence
Open document Open filing
Next action
Verify source filing
SCHEDULE 13G

SCHEDULE 13G filing

Filing date
03 Dec 2025
Reporting date
Not listed
SEC evidence
Open document Open filing
Next action
Verify source filing
SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
26 Nov 2025
Reporting date
Not listed
SEC evidence
Open document Open filing
Next action
Verify source filing
13F-HR

13F-HR filing

Filing date
13 Nov 2025
Reporting date
30 Sep 2025
SEC evidence
Open document Open filing
Next action
Verify source filing
SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
06 Nov 2025
Reporting date
Not listed
SEC evidence
Open document Open filing
Next action
Verify source filing
SCHEDULE 13G/A

SCHEDULE 13G/A filing

Filing date
30 Oct 2025
Reporting date
Not listed
SEC evidence
Open document Open filing
Next action
Verify source filing
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