Vault-13

JATT II ACQUISITION CORP JATT

ORD SHS · Common Stock · CUSIP G50765109

25 institutional holders
5,662,6825.7m shares reported held*
70.6% of all shares outstanding*
$64.3mreported value*

* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once. Holder counts are more reliable. Shares outstanding: 8.0m as of 2026-05-28, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $11.36.

Biggest buyers

Balyasny Asset Management L.P. New +500,000+500.0k
GREAT POINT PARTNERS LLC New +500,000+500.0k
RA CAPITAL MANAGEMENT, L.P. New +500,000+500.0k
Nantahala Capital Management, LLC New +450,000+450.0k
ADAR1 Capital Management, LLC New +417,724+417.7k
Atika Capital Management LLC New +400,000+400.0k
FRANKLIN RESOURCES INC New +400,000+400.0k
CITADEL ADVISORS LLC New +319,986+320.0k
BRAIDWELL LP New +250,000+250.0k
TCG Crossover Management, LLC New +200,000+200.0k

Biggest sellers

None

Major shareholders (over 5%)

Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.

HolderStakeChangeShares Last filed
JATT Ventures II L.P. 13D · may seek influence no change · filed 2026-09-18
Stated purposeOn February 12, 2026, the Sponsor paid $25,000, or approximately $0.014 per share, to cover certain of the Issuer's offering costs in exchange for 1,725,000 Founder Shares (the "Founder Shares"), of which 225,000 founder shares were forfeited subject to the expiration of the underwriters' over-allotment option, pursuant to the Securities Subscription Agreement dated as of February 12, 2026 between the Sponsor and the Issuer (the "Founder Share Purchase Agreement"). On April 20, 2026, the Issuer consummated its initial public offering ("IPO") and in connection with the consummation, Sponsor purchased an aggregate of 300,000 private placement shares for an aggregate purchase price of $3,000,000. The reporting persons made the acquisitions reported in this Schedule 13D in support of the Issue… Full filing
23.1% no change 1.8m≈ $20.4m 2026-09-18
RA CAPITAL MANAGEMENT, L.P. 13G · passive investor new · filed 2026-04-27 6.4% new 500.0k≈ $5.7m 2026-04-27
GREAT POINT PARTNERS LLC 13G · passive investor -0.2 pts · filed 2026-08-14 6.2% -0.2 pts 500.0k≈ $5.7m 2026-08-14
BALYASNY ASSET MANAGEMENT L.P. 13G · institution new · filed 2026-08-14 6.2% new 500.0k≈ $5.7m 2026-08-14
Janus Henderson Group Ltd. 13G · institution new · filed 2026-08-13 6.2% new 500.0k≈ $5.7m 2026-08-13
ADAR1 Capital Management, LLC 13G · institution new · filed 2026-08-14 5.4% new 417.7k≈ $4.7m 2026-08-14
Atika Capital Management LLC 13G · institution new · filed 2026-08-14 5.1% new 400.0k≈ $4.5m 2026-08-14

Fell to 5% or below in the last year: Commodore Capital LP (0.0%, 2026-08-14)

Insider purchases and sales since 1 Apr 2026

Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.

Officers and directors buying vs selling

Number of people, by quarter (10% owners not included)

BuyingSelling
101Q4 24: 0 buyingQ4 24: 0 sellingQ1 25: 0 buyingQ1 25: 0 sellingQ1 25Q2 25: 0 buyingQ2 25: 0 sellingQ3 25: 0 buyingQ3 25: 0 sellingQ3 25Q4 25: 0 buyingQ4 25: 0 sellingQ1 26: 0 buyingQ1 26: 0 sellingQ1 26Q2 26: 1 buyingQ2 26: 0 sellingQ3 26: 0 buyingQ3 26: 0 sellingQ3 26
Numbers
QuarterBuyingBoughtSellingSoldSold under a plan
Q4 20240—0——
Q1 20250—0——
Q2 20250—0——
Q3 20250—0——
Q4 20250—0——
Q1 20260—0——
Q2 20261—0——
Q3 20260—0——
DateInsiderTradeSharesPrice ValueTheir holding
2026-04-20 Sidhu Someit Chief Executive Officer, director · See Footnote Bought 300,000 — —300.0k shares +17%
2026-04-20 JATT Ventures II L.P. 10% owner Bought 300,000 — —300.0k shares +17%

Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).

Holders, Q2 2026

#ManagerLocationShares Value% of their portfolioChangeShares change
1 Balyasny Asset Management L.P. 0.01% of their portfolio Chicago, IL 500,000500.0k $5.7m $5.7m 0.01% New
2 GREAT POINT PARTNERS LLC 1.34% of their portfolio Greenwich, CT 500,000500.0k $5.7m $5.7m 1.34% New
3 RA CAPITAL MANAGEMENT, L.P. 0.05% of their portfolio BOSTON, MA 500,000500.0k $5.7m $5.7m 0.05% New
4 Jupiter Topco LLC 0.00% of their portfolio NEW YORK, NY 500,000500.0k $5.7m $5.7m 0.00% First filing
5 Nantahala Capital Management, LLC 0.15% of their portfolio NEW CANAAN, CT 450,000450.0k $5.1m $5.1m 0.15% New
6 ADAR1 Capital Management, LLC 0.22% of their portfolio AUSTIN, TX 417,724417.7k $4.7m $4.7m 0.22% New
7 FRANKLIN RESOURCES INC 0.00% of their portfolio San Mateo, CA 400,000400.0k $4.5m $4.5m 0.00% New
8 Atika Capital Management LLC 0.45% of their portfolio NEW YORK, NY 400,000400.0k $4.5m $4.5m 0.45% New
9 CITADEL ADVISORS LLC 0.00% of their portfolio MIAMI, FL 319,986320.0k $3.6m $3.6m 0.00% New
10 FARALLON CAPITAL MANAGEMENT, L.L.C. 0.02% of their portfolio SAN FRANCISCO, CA 300,000300.0k $3.4m $3.4m 0.02% Not comparable
11 BRAIDWELL LP 0.11% of their portfolio STAMFORD, CT 250,000250.0k $2.8m $2.8m 0.11% New
12 Affinity Asset Advisors, LLC 0.11% of their portfolio NEW YORK, NY 200,000200.0k $2.3m $2.3m 0.11% New
13 TCG Crossover Management, LLC 0.05% of their portfolio PALO ALTO, CA 200,000200.0k $2.3m $2.3m 0.05% New
14 Spruce Street Capital LP 0.36% of their portfolio NEW YORK, NY 160,000160.0k $1.8m $1.8m 0.36% New
15 MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio NEW YORK, NY 159,683159.7k $1.8m $1.8m 0.00% New
16 Logos Global Management LP 0.05% of their portfolio San Francisco, CA 100,000100.0k $1.1m $1.1m 0.05% New
17 TWO SIGMA INVESTMENTS, LP 0.00% of their portfolio NEW YORK, NY 96,16596.2k $1.1m $1.1m 0.00% New
18 TORONTO DOMINION BANK 0.00% of their portfolio TORONTO, ONTARIO, A6 50,50050.5k $573.7k $573.7k 0.00% New
19 Woodline Partners LP 0.00% of their portfolio San Francisco, CA 50,00050.0k $568.0k $568.0k 0.00% New
20 Magnetar Financial LLC 0.00% of their portfolio EVANSTON, IL 47,90847.9k $544.2k $544.2k 0.00% New
21 683 Capital Management, LLC 0.04% of their portfolio NEW YORK, NY 42,26442.3k $480.1k $480.1k 0.04% New
22 DIADEMA PARTNERS LP 0.04% of their portfolio MORRISTOWN, NJ 9,0219.0k $102.5k $102.5k 0.04% New
23 Clear Street Group Inc. 0.00% of their portfolio NEW YORK, NY 7,1237.1k $80.9k $80.9k 0.00% New
24 Persistent Asset Partners Ltd 0.01% of their portfolio HONG KONG, K3 2,3002.3k $26.1k $26.1k 0.01% New
25 MORGAN STANLEY 0.00% of their portfolio NEW YORK, NY 88 $91 $91 0.00% New