DexCom, Inc.
US ˙ NasdaqGS ˙ US2521311074

SecurityDXCM / DexCom, Inc.
InstitutionCitigroup Inc
Latest Disclosed Ownership834,087 shares
Latest Disclosed Value $ 52,380,663
Citigroup Inc ownership in DXCM / DexCom, Inc.

On May 11, 2026 - Citigroup Inc filed a 13F-HR form disclosing ownership of 834,087 shares of DexCom, Inc. (US:DXCM) valued at $52,380,664 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 846,003 shares of DexCom, Inc.. This represents a change in shares of -1.41% during the quarter. The current value of the position is $60,696,511 USD.

Citigroup Inc has a history of taking positions in derivatives of the underlying security (DXCM) in the form of stock options. The firm currently holds call options representing 50,000 of underlying shares valued at $3,140,000 USD and put options representing 98,000 of underlying shares valued at $6,154,400 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.

DXCM / DexCom, 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)
2026-05-11 2026-03-31 13F DEXCOM COM 252131107 834,087 -11,916 -1.41 52,381 -6.71 0.0112
2026-02-13 2025-12-31 13F DEXCOM COM 252131107 846,003 190,812 29.12 56,149 27.36 0.0248
2025-11-10 2025-09-30 13F DEXCOM COM 252131107 655,191 -39,807 -5.73 44,088 -27.33 0.0197
2025-08-11 2025-06-30 13F DEXCOM COM 252131107 694,998 -383,944 -35.59 60,666 -17.66 0.0298
2025-05-12 2025-03-31 13F DEXCOM COM 252131107 1,078,942 -119,760 -9.99 73,681 -20.96 0.0377
2025-02-12 2024-12-31 13F DEXCOM COM 252131107 1,198,702 275,970 29.91 93,223 50.70 0.0553
2024-11-12 2024-09-30 13F DEXCOM COM 252131107 922,732 287,234 45.20 61,860 -14.15 0.0358
2024-08-12 2024-06-30 13F DEXCOM COM 252131107 635,498 -117,444 -15.60 72,053 -31.01 0.0462
2024-05-10 2024-03-31 13F DEXCOM COM 252131107 752,942 -120,628 -13.81 104,433 -3.66 0.0686
2024-02-09 2023-12-31 13F DEXCOM COM 252131107 873,570 404,266 86.14 108,401 147.57 0.0764
2023-12-06 2023-09-30 13F/A-1 DEXCOM COM 252131107 469,304 -101,009 -17.71 43,786 -40.26 0.0327
2023-11-09 2023-09-30 13F DEXCOM COM 252131107 469,304 -101,009 43,786 0.0131
2023-08-10 2023-06-30 13F DEXCOM COM 252131107 570,313 -38,223 -6.28 73,291 3.66 0.0481
2023-05-11 2023-03-31 13F DEXCOM COM 252131107 608,536 -259,520 -29.90 70,700 -28.08 0.0496
2023-02-09 2022-12-31 13F DEXCOM COM 252131107 868,056 120,283 16.09 98,299 63.22 0.0783
2022-11-10 2022-09-30 13F DEXCOM COM 252131107 747,773 217,402 40.99 60,225 52.36 0.0431
2022-08-10 2022-06-30 13F DEXCOM COM 252131107 530,371 359,159 209.77 39,528 -54.87 0.0294
2022-05-12 2022-03-31 13F DEXCOM COM 252131107 171,212 -1,739 -1.01 87,592 -5.68 0.0532
2022-02-10 2021-12-31 13F DEXCOM COM 252131107 172,951 -22,484 -11.50 92,867 -13.11 0.0497
2021-11-10 2021-09-30 13F DEXCOM COM 252131107 195,435 -28,041 -12.55 106,876 12.00 0.0631
2021-08-10 2021-06-30 13F DEXCOM COM 252131107 223,476 31,557 16.44 95,424 38.35 0.0574
2021-05-13 2021-03-31 13F DEXCOM COM 252131107 191,919 18,334 10.56 68,974 7.47 0.0446
2021-02-11 2020-12-31 13F DEXCOM COM 252131107 173,585 57,246 49.21 64,178 33.82 0.0379
2020-11-12 2020-09-30 13F DEXCOM COM 252131107 116,339 15,387 15.24 47,957 17.18 0.0313
2020-08-12 2020-06-30 13F DEXCOM COM 252131107 100,952 28,216 38.79 40,926 108.96 0.0319
2020-05-12 2020-03-31 13F DEXCOM COM 252131107 72,736 4,712 6.93 19,586 31.64 0.0177
2020-02-12 2019-12-31 13F DEXCOM COM 252131107 68,024 13,497 24.75 14,879 82.81 0.0108
2019-11-08 2019-09-30 13F DEXCOM COM 252131107 54,527 18,670 52.07 8,139 51.51 0.0065
2019-08-12 2019-06-30 13F DEXCOM COM 252131107 35,857 -7,158 -16.64 5,372 4.86 0.0043
2019-05-13 2019-03-31 13F DEXCOM COM 252131107 43,015 9,114 26.88 5,123 26.18 0.0049
2019-02-12 2018-12-31 13F DEXCOM COM 252131107 33,901 25,148 287.31 4,060 224.28 0.0041
2018-11-13 2018-09-30 13F DEXCOM COM 252131107 8,753 4,433 102.62 1,252 206.11 0.0011
2018-08-10 2018-06-30 13F DEXCOM COM 252131107 4,320 -9,708 -69.20 409 -60.71 0.0004
2018-05-11 2018-03-31 13F DEXCOM COM 252131107 14,028 7,907 129.18 1,041 196.58 0.0009
2018-02-12 2017-12-31 13F DEXCOM COM 252131107 6,121 -7,009 -53.38 351 -45.33 0.0003
2017-11-13 2017-09-30 13F DEXCOM COM 252131107 13,130 69 0.53 642 -32.77 0.0005
2017-08-11 2017-06-30 13F DEXCOM COM 252131107 13,061 -2,102 -13.86 955 -25.62 0.0009
2017-05-12 2017-03-31 13F DEXCOM COM 252131107 15,163 -7,737 -33.79 1,284 -6.07 0.0011
2017-02-10 2016-12-31 13F DEXCOM COM 252131107 22,900 5,790 33.84 1,367 -8.87 0.0012
2016-11-10 2016-09-30 13F DEXCOM COM 252131107 17,110 5,223 43.94 1,500 59.07 0.0014
2016-08-12 2016-06-30 13F DEXCOM COM 252131107 11,887 12 0.10 943 16.85 0.0010
2016-05-13 2016-03-31 13F DEXCOM COM 252131107 11,875 103 0.87 807 -16.20 0.0009
2016-02-12 2015-12-31 13F DEXCOM COM 252131107 11,772 277 2.41 963 -2.43 0.0010
2015-11-13 2015-09-30 13F DEXCOM COM 252131107 11,495 -243 -2.07 987 5.00 0.0009
2015-08-13 2015-06-30 13F DEXCOM COM 252131107 11,738 -276 -2.30 940 25.67 0.0008
2015-05-14 2015-03-31 13F DEXCOM COM 252131107 12,014 1,066 9.74 748 24.05 0.0007
2015-02-17 2014-12-31 13F DEXCOM COM 252131107 10,948 -2,447 -18.27 603 12.50 0.0005
2014-11-14 2014-09-30 13F DEXCOM COM 252131107 13,395 5,402 67.58 536 68.55 0.0005
2014-08-14 2014-06-30 13F DEXCOM COM 252131107 7,993 849 11.88 318 7.43 0.0003
2014-05-15 2014-03-31 13F DEXCOM COM 252131107 7,144 -303 -4.07 296 12.12 0.0003
2014-02-14 2013-12-31 13F DEXCOM COM 252131107 7,447 253 3.52 264 30.05 0.0002
2013-11-14 2013-09-30 13F DEXCOM COM 252131107 7,194 -146 -1.99 203 23.78 0.0002
2013-08-14 2013-06-30 13F DEXCOM COM 252131107 7,340 7,340 164 0.0002
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
(%)
2026-05-11 2026-03-31 13F DEXCOM COM Call 50,000 -70.59 3,140 -72.17 n/a n/a n/a
2026-02-13 2025-12-31 13F DEXCOM COM Call 170,000 142.86 11,283 139.53 n/a n/a n/a
2025-11-10 2025-09-30 13F DEXCOM COM Call 70,000 75.00 4,710 34.92 n/a n/a n/a
2025-08-11 2025-06-30 13F DEXCOM COM Call 40,000 -66.67 3,492 -57.40 n/a n/a n/a
2025-05-12 2025-03-31 13F DEXCOM COM Call 120,000 -54.51 8,195 -60.06 n/a n/a n/a
2025-02-12 2024-12-31 13F DEXCOM COM Call 263,800 154.14 20,516 194.84 n/a n/a n/a
2024-11-12 2024-09-30 13F DEXCOM COM Call 103,800 -21.24 6,959 -53.44 n/a n/a n/a
2024-08-12 2024-06-30 13F DEXCOM COM Call 131,800 106.58 14,943 68.87 n/a n/a n/a
2024-05-10 2024-03-31 13F DEXCOM COM Call 63,800 0.00 8,849 11.79 n/a n/a n/a
2024-02-09 2023-12-31 13F DEXCOM COM Call 63,800 0.00 7,917 33.00 n/a n/a n/a
2023-12-06 2023-09-30 13F/A DEXCOM COM Call 63,800 -28.07 5,953 -47.78 n/a n/a n/a
2023-11-09 2023-09-30 13F DEXCOM COM Call 63,800 5,953 n/a n/a n/a
2023-08-10 2023-06-30 13F DEXCOM COM Call 88,700 4,335.00 11,399 4,812.93 n/a n/a n/a
2023-05-11 2023-03-31 13F DEXCOM COM Call 2,000 -96.00 232 -95.90 n/a n/a n/a
2023-02-09 2022-12-31 13F DEXCOM COM Call 50,000 5,662 n/a n/a n/a
2021-05-13 2021-03-31 13F DEXCOM COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-02-11 2020-12-31 13F DEXCOM COM Call 43,200 46.94 15,972 31.78 n/a n/a n/a
2020-11-12 2020-09-30 13F DEXCOM COM Call 29,400 -17.65 12,120 -16.26 n/a n/a n/a
2020-08-12 2020-06-30 13F DEXCOM COM Call 35,700 63.01 14,473 145.43 n/a n/a n/a
2020-05-12 2020-03-31 13F DEXCOM COM Call 21,900 5.80 5,897 30.23 n/a n/a n/a
2020-02-12 2019-12-31 13F DEXCOM COM Call 20,700 53.33 4,528 124.71 n/a n/a n/a
2019-11-08 2019-09-30 13F DEXCOM COM Call 13,500 0.00 2,015 -0.40 n/a n/a n/a
2019-08-12 2019-06-30 13F DEXCOM COM Call 13,500 128.81 2,023 187.77 n/a n/a n/a
2019-05-13 2019-03-31 13F DEXCOM COM Call 5,900 227.78 703 225.46 n/a n/a n/a
2019-02-12 2018-12-31 13F DEXCOM COM Call 1,800 -75.34 216 -79.31 n/a n/a n/a
2018-11-13 2018-09-30 13F DEXCOM COM Call 7,300 102.78 1,044 205.26 n/a n/a n/a
2018-08-10 2018-06-30 13F DEXCOM COM Call 3,600 176.92 342 256.25 n/a n/a n/a
2018-05-11 2018-03-31 13F DEXCOM COM Call 1,300 -71.74 96 -63.64 n/a n/a n/a
2018-02-12 2017-12-31 13F DEXCOM COM Call 4,600 -65.15 264 -59.13 n/a n/a n/a
2017-11-13 2017-09-30 13F DEXCOM COM Call 13,200 120.00 646 47.15 n/a n/a n/a
2017-08-11 2017-06-30 13F DEXCOM COM Call 6,000 172.73 439 136.02 n/a n/a n/a
2017-05-12 2017-03-31 13F DEXCOM COM Call 2,200 57.14 186 121.43 n/a n/a n/a
2017-02-10 2016-12-31 13F DEXCOM COM Call 1,400 100.00 84 37.70 n/a n/a n/a
2016-11-10 2016-09-30 13F DEXCOM COM Call 700 61 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
(%)
2026-05-11 2026-03-31 13F DEXCOM COM Put 98,000 -47.87 6,154 -50.68 n/a n/a n/a
2026-02-13 2025-12-31 13F DEXCOM COM Put 188,000 52.85 12,478 50.76 n/a n/a n/a
2025-11-10 2025-09-30 13F DEXCOM COM Put 123,000 95.24 8,277 50.50 n/a n/a n/a
2025-08-11 2025-06-30 13F DEXCOM COM Put 63,000 -82.15 5,499 -77.19 n/a n/a n/a
2025-05-12 2025-03-31 13F DEXCOM COM Put 353,000 -9.02 24,106 -20.11 n/a n/a n/a
2025-02-12 2024-12-31 13F DEXCOM COM Put 388,000 26.38 30,175 46.61 n/a n/a n/a
2024-11-12 2024-09-30 13F DEXCOM COM Put 307,000 149.59 20,581 47.59 n/a n/a n/a
2024-08-12 2024-06-30 13F DEXCOM COM Put 123,000 13,946 n/a n/a n/a
2024-05-10 2024-03-31 13F DEXCOM COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-02-09 2023-12-31 13F DEXCOM COM Put 125,000 0.00 15,511 33.00 n/a n/a n/a
2023-12-06 2023-09-30 13F/A DEXCOM COM Put 125,000 0.00 11,662 -27.40 n/a n/a n/a
2023-11-09 2023-09-30 13F DEXCOM COM Put 125,000 11,662 n/a n/a n/a
2023-08-10 2023-06-30 13F DEXCOM COM Put 125,000 -54.55 16,064 -49.72 n/a n/a n/a
2023-05-11 2023-03-31 13F DEXCOM COM Put 275,000 1.10 31,950 3.73 n/a n/a n/a
2023-02-09 2022-12-31 13F DEXCOM COM Put 272,000 -31.49 30,801 -3.67 n/a n/a n/a
2022-11-10 2022-09-30 13F DEXCOM COM Put 397,000 694.00 31,974 757.90 n/a n/a n/a
2022-08-10 2022-06-30 13F DEXCOM COM Put 50,000 3,727 n/a n/a n/a
2022-05-12 2022-03-31 13F DEXCOM COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-02-10 2021-12-31 13F DEXCOM COM Put 10,000 5,370 n/a n/a n/a
2021-05-13 2021-03-31 13F DEXCOM COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-02-11 2020-12-31 13F DEXCOM COM Put 37,800 47.66 13,975 32.43 n/a n/a n/a
2020-11-12 2020-09-30 13F DEXCOM COM Put 25,600 8.47 10,553 10.31 n/a n/a n/a
2020-08-12 2020-06-30 13F DEXCOM COM Put 23,600 -37.40 9,567 -5.75 n/a n/a n/a
2020-05-12 2020-03-31 13F DEXCOM COM Put 37,700 2.17 10,151 25.76 n/a n/a n/a
2020-02-12 2019-12-31 13F DEXCOM COM Put 36,900 339.29 8,072 543.70 n/a n/a n/a
2019-11-08 2019-09-30 13F DEXCOM COM Put 8,400 -58.62 1,254 -58.78 n/a n/a n/a
2019-08-12 2019-06-30 13F DEXCOM COM Put 20,300 89.72 3,042 138.78 n/a n/a n/a
2019-05-13 2019-03-31 13F DEXCOM COM Put 10,700 160.98 1,274 159.47 n/a n/a n/a
2019-02-12 2018-12-31 13F DEXCOM COM Put 4,100 -63.39 491 -69.35 n/a n/a n/a
2018-11-13 2018-09-30 13F DEXCOM COM Put 11,200 460.00 1,602 743.16 n/a n/a n/a
2018-08-10 2018-06-30 13F DEXCOM COM Put 2,000 -69.23 190 -60.58 n/a n/a n/a
2018-05-11 2018-03-31 13F DEXCOM COM Put 6,500 -10.96 482 15.04 n/a n/a n/a
2018-02-12 2017-12-31 13F DEXCOM COM Put 7,300 15.87 419 36.04 n/a n/a n/a
2017-11-13 2017-09-30 13F DEXCOM COM Put 6,300 96.88 308 31.62 n/a n/a n/a
2017-08-11 2017-06-30 13F DEXCOM COM Put 3,200 -37.25 234 -45.83 n/a n/a n/a
2017-05-12 2017-03-31 13F DEXCOM COM Put 5,100 -52.78 432 -33.02 n/a n/a n/a
2017-02-10 2016-12-31 13F DEXCOM COM Put 10,800 61.19 645 9.88 n/a n/a n/a
2016-11-10 2016-09-30 13F DEXCOM COM Put 6,700 587 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.