OS in the 13F filings

Onestream Inc · CUSIP 68278B107

Quarter

Q1 2026 Q4 2025 Q3 2025 Q2 2025 Q1 2025 Q4 2024 Q3 2024

Quarter end: 31 Mar 2026; the date the book describes
Filed: 27 Oct 2026; latest of these filings; the earliest 12 May 2026
Managers listing it: 21; at least, of 95 tracked, among listed positions
Comparable managers: 91; filed both Q4 2025 and Q1 2026; 3 listed it in both
Shares listed: 14,746,314; combined, among listed positions
Reported value: $345m; combined, at the quarter end

AllianceBernstein LP. Values in this filing are at the previous quarter end's prices; its share count is the quarter end's.

Among the 91 comparable managers: 15 buyers (opened or added shares) and 13 sellers (trimmed or exited), at least, among listed positions. Their net change in shares was +1,427,469.

Managers listing OS in Q1 2026

Share of 13F value is the position’s reported value over everything the manager reported that quarter. The share change is against Q4 2025, and only where both filings list the position. A rise in value with no rise in shares is the price, not buying.

ActionShare of book at least

21 of 21 holders

				Action		Filing
Millennium Management LLC	2,471,107	$59m	under 0.1%	Added	+2,135,526	15 May 2026 (the filing on sec.gov)
Man Group PLC	2,204,520	$53m	0.10%	New	new	15 May 2026 (the filing on sec.gov)
Citadel Advisors LLC	1,890,118	$45m	under 0.1%	Trimmed	-382,193	15 May 2026 (the filing on sec.gov)
Soros Fund Management LLC	1,830,222	$44m	0.48%	Added	+1,500,222	15 May 2026 (the filing on sec.gov)
AllianceBernstein LP	1,535,061	$28m	under 0.1%	New	new	15 May 2026 (the filing on sec.gov)
Marshall Wace LLP	990,806	$24m	under 0.1%	Trimmed	-1,795,349	15 May 2026 (the filing on sec.gov)
Susquehanna International Group LLP	984,652	$24m	under 0.1%	Added	+857,444	15 May 2026 (the filing on sec.gov)
Verition Fund Management LLC	862,413	$21m	0.13%	Added	+848,713	15 May 2026 (the filing on sec.gov)
Balyasny Asset Management LLC	817,569	$20m	under 0.1%	Added	+407,944	15 May 2026 (the filing on sec.gov)
Squarepoint Ops LLC	518,231	$12m	under 0.1%	New	new	15 May 2026 (the filing on sec.gov)
AQR Capital Management LLC	326,514	$7.8m	under 0.1%	Added	+36,088	15 May 2026 (the filing on sec.gov)
Jane Street Group LLC	106,508	$2.6m	under 0.1%	Trimmed	-133,533	12 May 2026 (the filing on sec.gov)
Fidelity (FMR LLC)	45,762	$1.1m	under 0.1%	Added	+701	15 May 2026 (the filing on sec.gov)
Point72 Asset Management LP	37,775	$907k	under 0.1%	Trimmed	-432,990	15 May 2026 (the filing on sec.gov)
Schonfeld Strategic Advisors LLC	33,709	$809k	under 0.1%	Added	+19,955	15 May 2026 (the filing on sec.gov)
Brevan Howard Capital Management LP	27,198	$653k	under 0.1%	Added	+16,974	15 May 2026 (the filing on sec.gov)
T. Rowe Price Associates Inc	21,355	$513k	under 0.1%	Added	+1,500	15 May 2026 (the filing on sec.gov)
GAMCO Investors Inc	15,000	$360k	under 0.1%	New	new	14 May 2026 (the filing on sec.gov)
Quantbot Technologies LP	14,382	$345k	under 0.1%	New	new	13 May 2026 (the filing on sec.gov)
Hudson Bay Capital Management LP	12,793	$307k	under 0.1%	Trimmed	-58,129	13 May 2026 (the filing on sec.gov)
ExodusPoint Capital Management LP	619	$15k	under 0.1%	Trimmed	-442,232	14 May 2026 (the filing on sec.gov)

Largest increases and reductions, by shares

Q4 2025 to Q1 2026, among managers that listed it in both quarters or opened it.

Increases

Man Group PLCnew position · 2,204,520 shares now+2,204,520
Millennium Management LLCexisting position · 2,471,107 shares now+2,135,526
AllianceBernstein LPnew position · 1,535,061 shares now+1,535,061
Soros Fund Management LLCexisting position · 1,830,222 shares now+1,500,222
Susquehanna International Group LLPexisting position · 984,652 shares now+857,444

Reductions

Marshall Wace LLPexisting position · 990,806 shares now-1,795,349
ExodusPoint Capital Management LPexisting position · 619 shares now-442,232
Point72 Asset Management LPexisting position · 37,775 shares now-432,990
Citadel Advisors LLCexisting position · 1,890,118 shares now-382,193
Jane Street Group LLCexisting position · 106,508 shares now-133,533

New positions and exits

At least these many: a manager is shown exiting only where its own filing shows the position gone.

New (5)

Exited (7)

Wellington Management Group LLPwas $25m
Neuberger Berman Group LLCwas $24m
Moore Capital Management LPwas $22m
MFS Investment Managementwas $19m
Voloridge Investment Management LLCwas $6.5m
Tudor Investment Corpwas $3.3m
Janus Henderson Group Ltdwas $539k

Ownership over time

Every quarter on file. A quarter-end value moves with the price as well as with the shares held; buyers and sellers count comparable managers, by shares.

7 in Q3 2024 to 3 in Q1 2026

Tracked managers listing it, at least.

the quarter shown share split complete books; unmarked quarters rest on listed positionsClick a quarter to open it.

Compare with…

Holders over time, buyers and sellers, and the managers holding both, side by side for up to four stocks.

Choose a stock to compare with OS →

How much of the picture this is

A 13F is a manager’s long US-listed equity book at a quarter end, filed up to 45 days later. It shows no shorts, cash, bonds or performance, and it is never today’s portfolio. Large books are listed to their largest positions, so a manager missing from this table may still hold a small position below that line. These are 95 tracked managers, not the institutional market.

Which funds own OS, latest filings →Back to the 13F Explorer →

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Quarter	Holders	Reported value	Buyers	Sellers
Q3 2024	7	$95m	7	0
Q4 2024	7	$73m	7	3
Q1 2025	3	$57m	2	2
Q2 2025	6	$150m	4	2
Q3 2025	3	$54m	2	1
Q4 2025	4	$88m	14	14
Q1 2026	3	$118m	15	13