Vanguard Index Funds - Vanguard Mid-Cap ETF
US ˙ ARCA ˙ US9229086296

SecurityVO / Vanguard Index Funds - Vanguard Mid-Cap ETF
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership6,348 shares
Latest Disclosed Value $ 1,823,019
Citadel Advisors Llc ownership in VO / Vanguard Index Funds - Vanguard Mid-Cap ETF

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 6,348 shares of Vanguard Index Funds - Vanguard Mid-Cap ETF (US:VO) valued at $1,823,019 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 0 shares of Vanguard Index Funds - Vanguard Mid-Cap ETF. The current value of the position is $504,983 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (VO) in the form of stock options. The firm currently holds call options representing 9,700 of underlying shares valued at $2,785,646 USD and put options representing 6,400 of underlying shares valued at $1,837,952 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.

VO / Vanguard Index Funds - Vanguard Mid-Cap ETF 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 VANGUARD INDEX FDS MID CAP ETF 922908629 6,348 6,348 1,823 0.0003
2026-02-17 2025-12-31 13F VANGUARD INDEX FDS MID CAP ETF 922908629 0 -12,564 -100.00 0 -100.00
2025-11-14 2025-09-30 13F VANGUARD INDEX FDS MID CAP ETF 922908629 12,564 12,564 3,691 0.0006
2025-08-14 2025-06-30 13F VANGUARD INDEX FDS MID CAP ETF 922908629 0 -487 -100.00 0 -100.00
2025-05-15 2025-03-31 13F VANGUARD INDEX FDS MID CAP ETF 922908629 487 -2,663 -84.54 126 -84.98 0.0000
2025-02-14 2024-12-31 13F VANGUARD INDEX FDS MID CAP ETF 922908629 3,150 -1,204 -27.65 832 -27.53 0.0001
2024-11-14 2024-09-30 13F VANGUARD INDEX FDS MID CAP ETF 922908629 4,354 -8,653 -66.53 1,149 -63.53 0.0002
2024-08-14 2024-06-30 13F VANGUARD INDEX FDS MID CAP ETF 922908629 13,007 155 1.21 3,149 -1.96 0.0006
2024-05-15 2024-03-31 13F VANGUARD INDEX FDS MID CAP ETF 922908629 12,852 -1,708 -11.73 3,211 -5.20 0.0006
2024-02-14 2023-12-31 13F VANGUARD INDEX FDS MID CAP ETF 922908629 14,560 7,979 121.24 3,387 147.23 0.0007
2023-11-14 2023-09-30 13F VANGUARD INDEX FDS MID CAP ETF 922908629 6,581 5,646 603.85 1,370 568.29 0.0003
2023-08-14 2023-06-30 13F VANGUARD INDEX FDS MID CAP ETF 922908629 935 -2,857 -75.34 206 -74.34 0.0000
2023-05-15 2023-03-31 13F VANGUARD INDEX FDS MID CAP ETF 922908629 3,792 -2,802 -42.49 800 -40.51 0.0002
2023-02-14 2022-12-31 13F VANGUARD INDEX FDS MID CAP ETF 922908629 6,594 -2,106 -24.21 1,344 -17.86 0.0003
2022-11-14 2022-09-30 13F VANGUARD INDEX FDS MID CAP ETF 922908629 8,700 6,241 253.80 1,635 237.81 0.0004
2022-08-15 2022-06-30 13F VANGUARD INDEX FDS MID CAP ETF 922908629 2,459 -4,943 -66.78 484 -72.50 0.0001
2022-05-16 2022-03-31 13F VANGUARD INDEX FDS MID CAP ETF 922908629 7,402 7,402 1,760 0.0004
2021-05-21 2021-03-31 13F/A-1 VANGUARD INDEX FDS MID CAP ETF 922908629 0 -2,000 -100.00 0 -100.00
2021-02-16 2020-12-31 13F VANGUARD INDEX FDS MID CAP ETF 922908629 2,000 2,000 414 0.0001
2020-02-14 2019-12-31 13F VANGUARD INDEX FDS Cmn 922908629 0 -2,910 -100.00 0 -100.00
2019-11-14 2019-09-30 13F VANGUARD INDEX FDS Cmn 922908629 2,910 2,910 488 0.0002
2019-05-15 2019-03-31 13F VANGUARD INDEX FDS Cmn 922908629 0 -9,590 -100.00 0 -100.00
2019-02-14 2018-12-31 13F VANGUARD INDEX FDS Cmn 922908629 9,590 9,590 1,325 0.0007
2018-11-13 2018-09-30 13F VANGUARD INDEX FDS Cmn 922908629 0 -8,954 -100.00 0 -100.00
2018-08-14 2018-06-30 13F/A-1 VANGUARD INDEX FDS Cmn 922908629 8,954 8,954 1,412 0.0007
2018-08-10 2018-06-30 13F VANGUARD INDEX FDS Cmn 922908629 8,954 8,954 1,412
2018-02-09 2017-12-31 13F VANGUARD INDEX FDS Cmn 922908629 0 -21,174 -100.00 0 -100.00
2017-11-09 2017-09-30 13F VANGUARD INDEX FDS Cmn 922908629 21,174 21,174 3,113 0.0024
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 VANGUARD INDEX FDS MID CAP ETF Call 9,700 51.56 2,786 49.97 n/a n/a n/a
2026-02-17 2025-12-31 13F VANGUARD INDEX FDS MID CAP ETF Call 6,400 3.23 1,857 1.98 n/a n/a n/a
2025-11-14 2025-09-30 13F VANGUARD INDEX FDS MID CAP ETF Call 6,200 40.91 1,821 47.93 n/a n/a n/a
2025-08-14 2025-06-30 13F VANGUARD INDEX FDS MID CAP ETF Call 4,400 22.22 1,231 32.22 n/a n/a n/a
2025-05-15 2025-03-31 13F VANGUARD INDEX FDS MID CAP ETF Call 3,600 5.88 931 3.67 n/a n/a n/a
2025-02-14 2024-12-31 13F VANGUARD INDEX FDS MID CAP ETF Call 3,400 6.25 898 6.40 n/a n/a n/a
2024-11-14 2024-09-30 13F VANGUARD INDEX FDS MID CAP ETF Call 3,200 33.33 844 45.27 n/a n/a n/a
2024-08-14 2024-06-30 13F VANGUARD INDEX FDS MID CAP ETF Call 2,400 -83.10 581 -83.62 n/a n/a n/a
2024-05-15 2024-03-31 13F VANGUARD INDEX FDS MID CAP ETF Call 14,200 -52.67 3,548 -49.16 n/a n/a n/a
2024-02-14 2023-12-31 13F VANGUARD INDEX FDS MID CAP ETF Call 30,000 84.05 6,979 105.63 n/a n/a n/a
2023-11-14 2023-09-30 13F VANGUARD INDEX FDS MID CAP ETF Call 16,300 -8.94 3,394 -13.86 n/a n/a n/a
2023-08-14 2023-06-30 13F VANGUARD INDEX FDS MID CAP ETF Call 17,900 -24.15 3,941 -20.84 n/a n/a n/a
2023-05-15 2023-03-31 13F VANGUARD INDEX FDS MID CAP ETF Call 23,600 -42.30 4,978 -40.29 n/a n/a n/a
2023-02-14 2022-12-31 13F VANGUARD INDEX FDS MID CAP ETF Call 40,900 -35.28 8,336 -29.84 n/a n/a n/a
2022-11-14 2022-09-30 13F VANGUARD INDEX FDS MID CAP ETF Call 63,200 45.62 11,880 38.96 n/a n/a n/a
2022-08-15 2022-06-30 13F VANGUARD INDEX FDS MID CAP ETF Call 43,400 187.42 8,549 138.07 n/a n/a n/a
2022-05-16 2022-03-31 13F VANGUARD INDEX FDS MID CAP ETF Call 15,100 -41.70 3,591 -45.58 n/a n/a n/a
2022-02-14 2021-12-31 13F VANGUARD INDEX FDS MID CAP ETF Call 25,900 48.00 6,599 59.28 n/a n/a n/a
2021-11-15 2021-09-30 13F VANGUARD INDEX FDS Cmn Call 17,500 -41.86 4,143 -42.01 n/a n/a n/a
2021-08-16 2021-06-30 13F VANGUARD INDEX FDS MID CAP ETF Call 30,100 50.50 7,144 61.37 n/a n/a n/a
2021-05-21 2021-03-31 13F/A VANGUARD INDEX FDS MID CAP ETF Call 20,000 4,427 n/a n/a n/a
2021-05-17 2021-03-31 13F VANGUARD INDEX FDS MID CAP ETF Call 20,000 4,427 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 VANGUARD INDEX FDS MID CAP ETF Put 6,400 4.92 1,838 3.79 n/a n/a n/a
2026-02-17 2025-12-31 13F VANGUARD INDEX FDS MID CAP ETF Put 6,100 12.96 1,770 11.60 n/a n/a n/a
2025-11-14 2025-09-30 13F VANGUARD INDEX FDS MID CAP ETF Put 5,400 12.50 1,586 18.09 n/a n/a n/a
2025-08-14 2025-06-30 13F VANGUARD INDEX FDS MID CAP ETF Put 4,800 33.33 1,343 44.25 n/a n/a n/a
2025-05-15 2025-03-31 13F VANGUARD INDEX FDS MID CAP ETF Put 3,600 -38.98 931 -40.24 n/a n/a n/a
2025-02-14 2024-12-31 13F VANGUARD INDEX FDS MID CAP ETF Put 5,900 180.95 1,558 181.23 n/a n/a n/a
2024-11-14 2024-09-30 13F VANGUARD INDEX FDS MID CAP ETF Put 2,100 2,000.00 554 2,208.33 n/a n/a n/a
2024-08-14 2024-06-30 13F VANGUARD INDEX FDS MID CAP ETF Put 100 -98.46 24 -98.52 n/a n/a n/a
2024-05-15 2024-03-31 13F VANGUARD INDEX FDS MID CAP ETF Put 6,500 62.50 1,624 74.62 n/a n/a n/a
2024-02-14 2023-12-31 13F VANGUARD INDEX FDS MID CAP ETF Put 4,000 -24.53 931 -15.68 n/a n/a n/a
2023-11-14 2023-09-30 13F VANGUARD INDEX FDS MID CAP ETF Put 5,300 20.45 1,104 13.95 n/a n/a n/a
2023-08-14 2023-06-30 13F VANGUARD INDEX FDS MID CAP ETF Put 4,400 -6.38 969 -2.32 n/a n/a n/a
2023-05-15 2023-03-31 13F VANGUARD INDEX FDS MID CAP ETF Put 4,700 -94.38 991 -94.19 n/a n/a n/a
2023-02-14 2022-12-31 13F VANGUARD INDEX FDS MID CAP ETF Put 83,700 2,361.76 17,059 2,569.48 n/a n/a n/a
2022-11-14 2022-09-30 13F VANGUARD INDEX FDS MID CAP ETF Put 3,400 -46.03 639 -48.51 n/a n/a n/a
2022-08-15 2022-06-30 13F VANGUARD INDEX FDS MID CAP ETF Put 6,300 -54.01 1,241 -61.91 n/a n/a n/a
2022-05-16 2022-03-31 13F VANGUARD INDEX FDS MID CAP ETF Put 13,700 53.93 3,258 43.71 n/a n/a n/a
2022-02-14 2021-12-31 13F VANGUARD INDEX FDS MID CAP ETF Put 8,900 102.27 2,267 117.56 n/a n/a n/a
2021-11-15 2021-09-30 13F VANGUARD INDEX FDS Cmn Put 4,400 238.46 1,042 237.22 n/a n/a n/a
2021-08-16 2021-06-30 13F VANGUARD INDEX FDS MID CAP ETF Put 1,300 -7.14 309 -0.32 n/a n/a n/a
2021-05-21 2021-03-31 13F/A VANGUARD INDEX FDS MID CAP ETF Put 1,400 310 n/a n/a n/a
2021-05-17 2021-03-31 13F VANGUARD INDEX FDS MID CAP ETF Put 1,400 310 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.