Glaukos Corporation
US ˙ NYSE ˙ US3773221029

SecurityGKOS / Glaukos Corporation
InstitutionCitigroup Inc
Latest Disclosed Ownership61,503 shares
Latest Disclosed Value $ 6,621,413
Citigroup Inc ownership in GKOS / Glaukos Corporation

On May 11, 2026 - Citigroup Inc filed a 13F-HR form disclosing ownership of 61,503 shares of Glaukos Corporation (US:GKOS) valued at $6,621,413 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 44,623 shares of Glaukos Corporation. This represents a change in shares of 37.83% during the quarter. The current value of the position is $7,484,915 USD.

Citigroup Inc has a history of taking positions in derivatives of the underlying security (GKOS) 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 0 of underlying shares valued at $0 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.

GKOS / Glaukos Corporation 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)
2026-05-11 2026-03-31 13F GLAUKOS COM 377322102 61,503 16,880 37.83 6,621 31.42 0.0014
2026-02-13 2025-12-31 13F GLAUKOS COM 377322102 44,623 22,711 103.65 5,038 182.08 0.0022
2025-11-10 2025-09-30 13F GLAUKOS COM 377322102 21,912 -34,689 -61.29 1,787 -69.45 0.0008
2025-08-11 2025-06-30 13F GLAUKOS COM 377322102 56,601 -20,945 -27.01 5,846 -23.40 0.0029
2025-05-12 2025-03-31 13F GLAUKOS COM 377322102 77,546 -3,406 -4.21 7,632 -37.12 0.0039
2025-02-12 2024-12-31 13F GLAUKOS COM 377322102 80,952 14,100 21.09 12,138 39.36 0.0072
2024-11-12 2024-09-30 13F GLAUKOS COM 377322102 66,852 31,344 88.27 8,709 107.26 0.0050
2024-08-12 2024-06-30 13F GLAUKOS COM 377322102 35,508 -12 -0.03 4,202 25.47 0.0027
2024-05-10 2024-03-31 13F GLAUKOS COM 377322102 35,520 6,632 22.96 3,349 45.86 0.0022
2024-02-09 2023-12-31 13F GLAUKOS COM 377322102 28,888 9,878 51.96 2,296 60.56 0.0016
2023-12-06 2023-09-30 13F/A-1 GLAUKOS COM 377322102 19,010 -158,060 -89.26 1,431 -88.66 0.0011
2023-11-09 2023-09-30 13F GLAUKOS COM 377322102 19,010 -158,060 1,431 0.0004
2023-08-10 2023-06-30 13F GLAUKOS COM 377322102 177,070 155,506 721.14 12,609 1,067.50 0.0083
2023-05-11 2023-03-31 13F GLAUKOS COM 377322102 21,564 -6,973 -24.43 1,080 -13.32 0.0008
2023-02-09 2022-12-31 13F GLAUKOS COM 377322102 28,537 -202,811 -87.66 1,246 -89.88 0.0010
2022-11-10 2022-09-30 13F GLAUKOS COM 377322102 231,348 210,752 1,023.27 12,317 1,217.33 0.0088
2022-08-10 2022-06-30 13F GLAUKOS COM 377322102 20,596 -152,428 -88.10 935 -90.65 0.0007
2022-05-12 2022-03-31 13F GLAUKOS COM 377322102 173,024 137,081 381.38 10,004 526.42 0.0061
2022-02-10 2021-12-31 13F GLAUKOS COM 377322102 35,943 10,122 39.20 1,597 28.38 0.0009
2021-11-10 2021-09-30 13F GLAUKOS COM 377322102 25,821 -578 -2.19 1,244 -44.44 0.0007
2021-08-10 2021-06-30 13F GLAUKOS COM 377322102 26,399 21,419 430.10 2,239 435.65 0.0013
2021-05-13 2021-03-31 13F GLAUKOS COM 377322102 4,980 -6,035 -54.79 418 -49.58 0.0003
2021-02-11 2020-12-31 13F GLAUKOS COM 377322102 11,015 -6,053 -35.46 829 -1.89 0.0005
2020-11-12 2020-09-30 13F GLAUKOS COM 377322102 17,068 -6,336 -27.07 845 -6.01 0.0006
2020-08-12 2020-06-30 13F GLAUKOS COM 377322102 23,404 -13,169 -36.01 899 -20.37 0.0007
2020-05-12 2020-03-31 13F GLAUKOS COM 377322102 36,573 25,204 221.69 1,129 82.39 0.0010
2020-02-12 2019-12-31 13F GLAUKOS COM 377322102 11,369 -6,488 -36.33 619 -44.53 0.0004
2019-11-08 2019-09-30 13F GLAUKOS COM 377322102 17,857 3,008 20.26 1,116 -0.27 0.0009
2019-08-12 2019-06-30 13F GLAUKOS COM 377322102 14,849 6,401 75.77 1,119 69.03 0.0009
2019-05-13 2019-03-31 13F GLAUKOS COM 377322102 8,448 612 7.81 662 50.45 0.0006
2019-02-12 2018-12-31 13F GLAUKOS COM 377322102 7,836 -15,770 -66.81 440 -71.28 0.0004
2018-11-13 2018-09-30 13F GLAUKOS COM 377322102 23,606 9,198 63.84 1,532 161.88 0.0014
2018-08-10 2018-06-30 13F GLAUKOS COM 377322102 14,408 12,258 570.14 585 773.13 0.0005
2018-05-11 2018-03-31 13F GLAUKOS COM 377322102 2,150 1,906 781.15 67 1,016.67 0.0001
2018-02-12 2017-12-31 13F GLAUKOS COM 377322102 244 -1,668 -87.24 6 -90.48 0.0000
2017-11-13 2017-09-30 13F GLAUKOS COM 377322102 1,912 19 1.00 63 -19.23 0.0001
2017-08-11 2017-06-30 13F GLAUKOS COM 377322102 1,893 255 15.57 78 -6.02 0.0001
2017-05-12 2017-03-31 13F GLAUKOS COM 377322102 1,638 -11,868 -87.87 83 -82.03 0.0001
2017-02-10 2016-12-31 13F GLAUKOS COM 377322102 13,506 11,232 493.93 462 437.21 0.0004
2016-11-10 2016-09-30 13F GLAUKOS COM 377322102 2,274 693 43.83 86 86.96 0.0001
2016-08-12 2016-06-30 13F GLAUKOS COM 377322102 1,581 -3,199 -66.92 46 -43.21 0.0000
2016-05-13 2016-03-31 13F GLAUKOS COM 377322102 4,780 4,146 653.94 81 406.25 0.0001
2016-02-12 2015-12-31 13F GLAUKOS COM 377322102 634 -2,223 -77.81 16 -77.14 0.0000
2015-11-13 2015-09-30 13F GLAUKOS COM 377322102 2,857 2,857 70 0.0001
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
(%)
2021-11-10 2021-09-30 13F GLAUKOS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-08-10 2021-06-30 13F GLAUKOS COM Call 100,000 8,483 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
(%)
2023-02-09 2022-12-31 13F GLAUKOS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-11-10 2022-09-30 13F GLAUKOS COM Put 120,000 6,389 n/a n/a n/a
2022-08-10 2022-06-30 13F GLAUKOS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-05-12 2022-03-31 13F GLAUKOS COM Put 80,000 4,626 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.