Fastly, Inc.
US ˙ NasdaqGS ˙ US31188V1008

SecurityFSLY / Fastly, Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership460,314 shares
Latest Disclosed Value $ 13,376,725
Citadel Advisors Llc ownership in FSLY / Fastly, Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 460,314 shares of Fastly, Inc. (US:FSLY) valued at $13,376,725 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 2,012,630 shares of Fastly, Inc.. This represents a change in shares of -77.13% during the quarter. The current value of the position is $8,317,874 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (FSLY) in the form of stock options. The firm currently holds call options representing 849,300 of underlying shares valued at $24,680,658 USD and put options representing 2,480,200 of underlying shares valued at $72,074,612 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.

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Institutional Put/Call Ratios
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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.

FSLY / Fastly, Inc. 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 FASTLY CL A 31188V100 460,314 -1,552,316 -77.13 13,377 -34.71 0.0019
2026-02-17 2025-12-31 13F FASTLY CL A 31188V100 2,012,630 1,343,738 200.89 20,489 258.24 0.0031
2025-11-14 2025-09-30 13F FASTLY CL A 31188V100 668,892 -159,637 -19.27 5,719 -2.22 0.0009
2025-08-14 2025-06-30 13F FASTLY CL A 31188V100 828,529 -309,458 -27.19 5,849 -18.80 0.0010
2025-05-15 2025-03-31 13F FASTLY CL A 31188V100 1,137,987 403,754 54.99 7,203 3.92 0.0014
2025-02-14 2024-12-31 13F FASTLY CL A 31188V100 734,233 -52,409 -6.66 6,931 16.41 0.0012
2024-11-14 2024-09-30 13F FASTLY CL A 31188V100 786,642 274,256 53.53 5,955 57.68 0.0011
2024-08-14 2024-06-30 13F FASTLY CL A 31188V100 512,386 55,538 12.16 3,776 -36.27 0.0008
2024-05-15 2024-03-31 13F FASTLY CL A 31188V100 456,848 237,458 108.24 5,925 51.73 0.0011
2024-02-14 2023-12-31 13F FASTLY CL A 31188V100 219,390 -80,581 -26.86 3,905 -32.09 0.0008
2023-11-14 2023-09-30 13F FASTLY CL A 31188V100 299,971 -1,850,705 -86.05 5,750 -83.05 0.0012
2023-08-14 2023-06-30 13F FASTLY CL A 31188V100 2,150,676 378,250 21.34 33,916 7.75 0.0070
2023-05-15 2023-03-31 13F FASTLY CL A 31188V100 1,772,426 272,949 18.20 31,478 156.34 0.0069
2023-02-14 2022-12-31 13F FASTLY CL A 31188V100 1,499,477 -406,259 -21.32 12,281 -29.66 0.0029
2022-11-14 2022-09-30 13F FASTLY CL A 31188V100 1,905,736 -176,249 -8.47 17,457 -27.78 0.0040
2022-08-15 2022-06-30 13F FASTLY CL A 31188V100 2,081,985 -187,486 -8.26 24,171 -38.72 0.0062
2022-05-16 2022-03-31 13F FASTLY CL A 31188V100 2,269,471 780,362 52.40 39,443 -25.28 0.0081
2022-02-14 2021-12-31 13F FASTLY CL A 31188V100 1,489,109 1,476,319 11,542.76 52,788 10,110.44 0.0108
2021-11-15 2021-09-30 13F FASTLY Cmn 31188V100 12,790 -1,722 -11.87 517 -40.23 0.0001
2021-08-16 2021-06-30 13F FASTLY CL A 31188V100 14,512 -697,190 -97.96 865 -98.19 0.0002
2021-05-21 2021-03-31 13F/A-1 FASTLY CL A 31188V100 711,702 524,731 280.65 47,883 193.13 0.0117
2021-05-17 2021-03-31 13F FASTLY CL A 31188V100 711,702 524,731 47,883 0.0117
2021-02-16 2020-12-31 13F FASTLY CL A 31188V100 186,971 47,096 33.67 16,335 24.66 0.0042
2020-11-16 2020-09-30 13F FASTLY CL A 31188V100 139,875 -51,369 -26.86 13,104 -19.51 0.0037
2020-08-14 2020-06-30 13F FASTLY Cmn 31188V100 191,244 142,170 289.71 16,281 1,648.76 0.0058
2020-05-15 2020-03-31 13F FASTLY Cmn 31188V100 49,074 -349,093 -87.68 931 -88.35 0.0004
2020-02-14 2019-12-31 13F FASTLY Cmn 31188V100 398,167 374,962 1,615.87 7,991 1,334.65 0.0035
2019-11-14 2019-09-30 13F FASTLY Cmn 31188V100 23,205 -160,941 -87.40 557 -85.08 0.0003
2019-08-14 2019-06-30 13F FASTLY Cmn 31188V100 184,146 184,146 3,734 0.0017
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
(%)
2026-05-15 2026-03-31 13F FASTLY CL A Call 849,300 326.78 24,681 1,118.77 n/a n/a n/a
2026-02-17 2025-12-31 13F FASTLY CL A Call 199,000 62.85 2,026 93.97 n/a n/a n/a
2025-11-14 2025-09-30 13F FASTLY CL A Call 122,200 -29.89 1,045 -15.12 n/a n/a n/a
2025-08-14 2025-06-30 13F FASTLY CL A Call 174,300 -28.89 1,231 -20.70 n/a n/a n/a
2025-05-15 2025-03-31 13F FASTLY CL A Call 245,100 -36.49 1,551 -57.41 n/a n/a n/a
2025-02-14 2024-12-31 13F FASTLY CL A Call 385,900 -50.67 3,643 -38.50 n/a n/a n/a
2024-11-14 2024-09-30 13F FASTLY CL A Call 782,300 -5.63 5,922 -3.06 n/a n/a n/a
2024-08-14 2024-06-30 13F FASTLY CL A Call 829,000 -45.93 6,110 -69.28 n/a n/a n/a
2024-05-15 2024-03-31 13F FASTLY CL A Call 1,533,300 102.76 19,887 47.74 n/a n/a n/a
2024-02-14 2023-12-31 13F FASTLY CL A Call 756,200 29.84 13,460 20.57 n/a n/a n/a
2023-11-14 2023-09-30 13F FASTLY CL A Call 582,400 70.29 11,165 107.01 n/a n/a n/a
2023-08-14 2023-06-30 13F FASTLY CL A Call 342,000 -35.03 5,393 -42.31 n/a n/a n/a
2023-05-15 2023-03-31 13F FASTLY CL A Call 526,400 -13.82 9,349 86.89 n/a n/a n/a
2023-02-14 2022-12-31 13F FASTLY CL A Call 610,800 -15.98 5,002 -24.89 n/a n/a n/a
2022-11-14 2022-09-30 13F FASTLY CL A Call 727,000 -25.73 6,660 -41.39 n/a n/a n/a
2022-08-15 2022-06-30 13F FASTLY CL A Call 978,800 -13.29 11,363 -42.08 n/a n/a n/a
2022-05-16 2022-03-31 13F FASTLY CL A Call 1,128,800 -2.82 19,618 -52.36 n/a n/a n/a
2022-02-14 2021-12-31 13F FASTLY CL A Call 1,161,500 -18.23 41,176 -28.32 n/a n/a n/a
2021-11-15 2021-09-30 13F FASTLY Cmn Call 1,420,500 -13.45 57,445 -41.27 n/a n/a n/a
2021-08-16 2021-06-30 13F FASTLY CL A Call 1,641,200 82.48 97,816 61.65 n/a n/a n/a
2021-05-21 2021-03-31 13F/A FASTLY CL A Call 899,400 -14.87 60,512 -34.44 n/a n/a n/a
2021-05-17 2021-03-31 13F FASTLY CL A Call 899,400 60,512 n/a n/a n/a
2021-02-16 2020-12-31 13F FASTLY CL A Call 1,056,500 52.12 92,306 41.88 n/a n/a n/a
2020-11-16 2020-09-30 13F FASTLY CL A Call 694,500 30.10 65,061 43.17 n/a n/a n/a
2020-08-14 2020-06-30 13F FASTLY Cmn Call 533,800 172.35 45,442 1,121.56 n/a n/a n/a
2020-05-15 2020-03-31 13F FASTLY Cmn Call 196,000 47.37 3,720 39.38 n/a n/a n/a
2020-02-14 2019-12-31 13F FASTLY Cmn Call 133,000 -33.40 2,669 -44.31 n/a n/a n/a
2019-11-14 2019-09-30 13F FASTLY Cmn Call 199,700 490.83 4,793 599.71 n/a n/a n/a
2019-08-14 2019-06-30 13F FASTLY Cmn Call 33,800 685 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 FASTLY CL A Put 2,480,200 672.41 72,075 2,105.45 n/a n/a n/a
2026-02-17 2025-12-31 13F FASTLY CL A Put 321,100 -13.73 3,269 2.70 n/a n/a n/a
2025-11-14 2025-09-30 13F FASTLY CL A Put 372,200 -14.32 3,182 3.78 n/a n/a n/a
2025-08-14 2025-06-30 13F FASTLY CL A Put 434,400 -39.17 3,067 -32.17 n/a n/a n/a
2025-05-15 2025-03-31 13F FASTLY CL A Put 714,100 98.64 4,520 33.22 n/a n/a n/a
2025-02-14 2024-12-31 13F FASTLY CL A Put 359,500 7.67 3,394 34.27 n/a n/a n/a
2024-11-14 2024-09-30 13F FASTLY CL A Put 333,900 -21.77 2,528 -19.65 n/a n/a n/a
2024-08-14 2024-06-30 13F FASTLY CL A Put 426,800 -53.14 3,146 -73.38 n/a n/a n/a
2024-05-15 2024-03-31 13F FASTLY CL A Put 910,800 209.38 11,813 125.44 n/a n/a n/a
2024-02-14 2023-12-31 13F FASTLY CL A Put 294,400 1.87 5,240 -5.42 n/a n/a n/a
2023-11-14 2023-09-30 13F FASTLY CL A Put 289,000 -35.96 5,540 -22.16 n/a n/a n/a
2023-08-14 2023-06-30 13F FASTLY CL A Put 451,300 -1.46 7,117 -12.50 n/a n/a n/a
2023-05-15 2023-03-31 13F FASTLY CL A Put 458,000 74.94 8,134 279.38 n/a n/a n/a
2023-02-14 2022-12-31 13F FASTLY CL A Put 261,800 8.90 2,144 -2.63 n/a n/a n/a
2022-11-14 2022-09-30 13F FASTLY CL A Put 240,400 -43.32 2,202 -55.28 n/a n/a n/a
2022-08-15 2022-06-30 13F FASTLY CL A Put 424,100 -42.35 4,924 -61.49 n/a n/a n/a
2022-05-16 2022-03-31 13F FASTLY CL A Put 735,700 10.70 12,787 -45.73 n/a n/a n/a
2022-02-14 2021-12-31 13F FASTLY CL A Put 664,600 -28.55 23,560 -37.37 n/a n/a n/a
2021-11-15 2021-09-30 13F FASTLY Cmn Put 930,200 -4.88 37,617 -35.46 n/a n/a n/a
2021-08-16 2021-06-30 13F FASTLY CL A Put 977,900 -3.23 58,283 -14.27 n/a n/a n/a
2021-05-21 2021-03-31 13F/A FASTLY CL A Put 1,010,500 2.87 67,986 -20.78 n/a n/a n/a
2021-05-17 2021-03-31 13F FASTLY CL A Put 1,010,500 67,986 n/a n/a n/a
2021-02-16 2020-12-31 13F FASTLY CL A Put 982,300 79.19 85,824 67.12 n/a n/a n/a
2020-11-16 2020-09-30 13F FASTLY CL A Put 548,200 55.47 51,355 71.09 n/a n/a n/a
2020-08-14 2020-06-30 13F FASTLY Cmn Put 352,600 65.77 30,017 643.55 n/a n/a n/a
2020-05-15 2020-03-31 13F FASTLY Cmn Put 212,700 -1.30 4,037 -6.66 n/a n/a n/a
2020-02-14 2019-12-31 13F FASTLY Cmn Put 215,500 78.10 4,325 48.93 n/a n/a n/a
2019-11-14 2019-09-30 13F FASTLY Cmn Put 121,000 2,904 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.