Similarweb Ltd.
DE ˙ DB ˙ IL0011751653
3,67 € ↑0,11 (3,03%)
2026-06-05
DEL PRIS
SecurityDE:63X / Similarweb Ltd.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership476,005 shares
Latest Disclosed Value $ 1,242,373
Citadel Advisors Llc ownership in 63X / Similarweb Ltd.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 476,005 shares of Similarweb Ltd. (DE:63X) valued at $1,032,931 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 200,114 shares of Similarweb Ltd.. This represents a change in shares of 137.87% during the quarter. The current value of the position is $1,745,986 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (63X) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 124,100 of underlying shares valued at $323,901 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

Upgrade to unlock premium data and export to Excel .

Institutional Put/Call Ratios
(Premium Subscription Required)

In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

DE:63X / Similarweb Ltd. Historical Put/Call Ratio
Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date
Effective
Date
Form Security Class ID Avg Price
Paid (Est)
Reported
Shares
ΔShares ΔShares
(%)
Reported
Value
(x1000)
ΔValue
(%)
Alloc
(%)
ΔAlloc ΔAlloc (%) Cost Basis
(x1000)
Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F SIMILARWEB SHS M84137104 476,005 275,891 137.87 1,242 -17.09 0.0002
2026-02-17 2025-12-31 13F SIMILARWEB SHS M84137104 200,114 -60,755 -23.29 1,499 -38.25 0.0002
2025-11-14 2025-09-30 13F SIMILARWEB SHS M84137104 260,869 -619,396 -70.36 2,426 -64.85 0.0004
2025-08-14 2025-06-30 13F SIMILARWEB SHS M84137104 880,265 380,265 76.05 6,901 66.89 0.0012
2025-05-15 2025-03-31 13F SIMILARWEB SHS M84137104 500,000 242,876 94.46 4,135 13.51 0.0008
2025-02-14 2024-12-31 13F SIMILARWEB SHS M84137104 257,124 -1,423,811 -84.70 3,643 -75.48 0.0006
2024-11-14 2024-09-30 13F SIMILARWEB SHS M84137104 1,680,935 1,571,630 1,437.84 14,859 1,650.18 0.0029
2024-08-14 2024-06-30 13F SIMILARWEB SHS M84137104 109,305 92,109 535.64 849 451.30 0.0002
2024-05-15 2024-03-31 13F SIMILARWEB SHS M84137104 17,196 -76,196 -81.59 155 -69.01 0.0000
2024-02-14 2023-12-31 13F SIMILARWEB SHS M84137104 93,392 93,392 498 0.0001
2023-11-14 2023-09-30 13F SIMILARWEB SHS M84137104 0 -19,936 -100.00 0 -100.00
2023-08-14 2023-06-30 13F SIMILARWEB SHS M84137104 19,936 -12,140 -37.85 131 -39.81 0.0000
2023-05-15 2023-03-31 13F SIMILARWEB SHS M84137104 32,076 32,076 217 0.0000
2023-02-14 2022-12-31 13F SIMILARWEB SHS M84137104 0 -46,202 -100.00 0 -100.00
2022-11-14 2022-09-30 13F SIMILARWEB SHS M84137104 46,202 -21,880 -32.14 271 -51.69 0.0001
2022-08-15 2022-06-30 13F SIMILARWEB SHS M84137104 68,082 -50,319 -42.50 561 -63.41 0.0001
2022-05-16 2022-03-31 13F SIMILARWEB SHS M84137104 118,401 -13,358 -10.14 1,533 -35.04 0.0003
2022-02-14 2021-12-31 13F SIMILARWEB SHS M84137104 131,759 93,221 241.89 2,360 192.80 0.0005
2021-11-15 2021-09-30 13F SIMILARWEB Cmn M84137104 38,538 -80,562 -67.64 806 -65.64 0.0002
2021-08-16 2021-06-30 13F SIMILARWEB SHS M84137104 119,100 119,100 2,346 0.0005
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-02-17 2025-12-31 13F SIMILARWEB SHS Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-11-14 2025-09-30 13F SIMILARWEB SHS Call 41,000 -36.43 381 -24.55 n/a n/a n/a
2025-08-14 2025-06-30 13F SIMILARWEB SHS Call 64,500 -21.82 506 -25.95 n/a n/a n/a
2025-05-15 2025-03-31 13F SIMILARWEB SHS Call 82,500 -41.53 682 -65.88 n/a n/a n/a
2025-02-14 2024-12-31 13F SIMILARWEB SHS Call 141,100 1,999 n/a n/a n/a
2024-08-14 2024-06-30 13F SIMILARWEB SHS Call 0 -100.00 0 -100.00 n/a n/a n/a
2024-05-15 2024-03-31 13F SIMILARWEB SHS Call 3,600 3,500.00 32 n/a n/a n/a
2024-02-14 2023-12-31 13F SIMILARWEB SHS Call 100 1 n/a n/a n/a
2023-11-14 2023-09-30 13F SIMILARWEB SHS Call 0 -100.00 0 -100.00 n/a n/a n/a
2023-08-14 2023-06-30 13F SIMILARWEB SHS Call 2,000 -52.38 13 -53.57 n/a n/a n/a
2023-05-15 2023-03-31 13F SIMILARWEB SHS Call 4,200 223.08 28 250.00 n/a n/a n/a
2023-02-14 2022-12-31 13F SIMILARWEB SHS Call 1,300 -90.51 8 -90.00 n/a n/a n/a
2022-11-14 2022-09-30 13F SIMILARWEB SHS Call 13,700 -14.91 80 -39.85 n/a n/a n/a
2022-08-15 2022-06-30 13F SIMILARWEB SHS Call 16,100 -1.23 133 -36.97 n/a n/a n/a
2022-05-16 2022-03-31 13F SIMILARWEB SHS Call 16,300 211 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F SIMILARWEB SHS Put 124,100 -56.59 324 -84.91 n/a n/a n/a
2026-02-17 2025-12-31 13F SIMILARWEB SHS Put 285,900 -53.70 2,141 -62.71 n/a n/a n/a
2025-11-14 2025-09-30 13F SIMILARWEB SHS Put 617,500 50.10 5,743 78.05 n/a n/a n/a
2025-08-14 2025-06-30 13F SIMILARWEB SHS Put 411,400 61.14 3,225 52.77 n/a n/a n/a
2025-05-15 2025-03-31 13F SIMILARWEB SHS Put 255,300 1,636.73 2,111 914.90 n/a n/a n/a
2025-02-14 2024-12-31 13F SIMILARWEB SHS Put 14,700 16.67 208 87.39 n/a n/a n/a
2024-11-14 2024-09-30 13F SIMILARWEB SHS Put 12,600 2,420.00 111 3,600.00 n/a n/a n/a
2024-08-14 2024-06-30 13F SIMILARWEB SHS Put 500 0.00 4 -25.00 n/a n/a n/a
2024-05-15 2024-03-31 13F SIMILARWEB SHS Put 500 -37.50 4 0.00 n/a n/a n/a
2024-02-14 2023-12-31 13F SIMILARWEB SHS Put 800 4 n/a n/a n/a
2023-11-14 2023-09-30 13F SIMILARWEB SHS Put 0 -100.00 0 -100.00 n/a n/a n/a
2023-08-14 2023-06-30 13F SIMILARWEB SHS Put 900 800.00 6 n/a n/a n/a
2023-05-15 2023-03-31 13F SIMILARWEB SHS Put 100 -99.78 1 -100.00 n/a n/a n/a
2023-02-14 2022-12-31 13F SIMILARWEB SHS Put 45,400 -19.65 292 -12.08 n/a n/a n/a
2022-11-14 2022-09-30 13F SIMILARWEB SHS Put 56,500 391.30 331 248.42 n/a n/a n/a
2022-08-15 2022-06-30 13F SIMILARWEB SHS Put 11,500 -68.23 95 -79.74 n/a n/a n/a
2022-05-16 2022-03-31 13F SIMILARWEB SHS Put 36,200 176.34 469 99.57 n/a n/a n/a
2022-02-14 2021-12-31 13F SIMILARWEB SHS Put 13,100 235 n/a n/a n/a
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.