西南航空公司
MX ˙ BMV ˙ US8447411088
SecurityMX:LUV / Southwest Airlines Co.
InstitutionMarshall Wace, Llp
Latest Disclosed Ownership509,456 shares
Latest Disclosed Value $ 19,140,261
Marshall Wace, Llp ownership in LUV / Southwest Airlines Co.

On May 14, 2026 - Marshall Wace, Llp filed a 13F-HR form disclosing ownership of 509,456 shares of Southwest Airlines Co. (MX:LUV) valued at $19,140,261 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 241,392 shares of Southwest Airlines Co.. This represents a change in shares of 111.05% during the quarter.

Marshall Wace, Llp has a history of taking positions in derivatives of the underlying security (LUV) 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.

MX:LUV / Southwest Airlines Co. 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)
2026-05-14 2026-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 509,456 268,064 111.05 19,140 91.86 0.0090
2026-02-13 2025-12-31 13F SOUTHWEST AIR COMMON STOCK 844741108 241,392 241,392 9,977 0.0091
2024-08-14 2024-06-30 13F SOUTHWEST AIR COMMON STOCK 844741108 0 -149,301 -100.00 0 -100.00
2024-05-15 2024-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 149,301 149,301 4,358 0.0066
2024-02-14 2023-12-31 13F SOUTHWEST AIR COMMON STOCK 844741108 0 -605,971 -100.00 0 -100.00
2023-11-14 2023-09-30 13F SOUTHWEST AIR COMMON STOCK 844741108 605,971 605,971 16,404 0.0332
2023-08-14 2023-06-30 13F SOUTHWEST AIR COMMON STOCK 844741108 0 -113,803 -100.00 0 -100.00
2023-05-15 2023-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 113,803 113,803 3,703 0.0079
2023-02-14 2022-12-31 13F SOUTHWEST AIR COMMON STOCK 844741108 0 -597,487 -100.00 0 -100.00
2022-11-14 2022-09-30 13F SOUTHWEST AIR COMMON STOCK 844741108 597,487 451,584 309.51 18,424 249.60 0.0404
2022-08-15 2022-06-30 13F SOUTHWEST AIR COMMON STOCK 844741108 145,903 -2,093,744 -93.49 5,270 -94.86 0.0108
2022-05-16 2022-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 2,239,647 2,239,647 102,574 0.1942
2022-02-14 2021-12-31 13F SOUTHWEST AIR COMMON STOCK 844741108 0 -145,974 -100.00 0 -100.00
2021-11-15 2021-09-30 13F SOUTHWEST AIR COMMON STOCK 844741108 145,974 76,343 109.64 7,507 103.06 0.0312
2021-08-13 2021-06-30 13F SOUTHWEST AIR COMMON STOCK 844741108 69,631 59,512 588.12 3,697 498.22 0.0180
2021-05-17 2021-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 10,119 10,119 -85.47 618 -83.28 0.0028
2020-11-16 2020-09-30 13F SOUTHWEST AIR COMMON STOCK 844741108 0 -109,028 -100.00 0 -100.00
2020-08-13 2020-06-30 13F SOUTHWEST AIR COMMON STOCK 844741108 109,028 87,260 400.86 3,726 380.77 0.0261
2020-05-15 2020-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 21,768 21,768 -80.03 775 -79.20 0.0077
2019-08-14 2019-06-30 13F SOUTHWEST AIR COMMON STOCK 844741108 0 -35,974 -100.00 0 -100.00
2019-05-29 2019-03-31 13F/A-1 SOUTHWEST AIR COMMON STOCK 844741108 35,974 -75,675 -67.78 1,868 -64.00 0.0176
2019-05-14 2019-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 35,974 -75,675 1,868
2019-02-14 2018-12-31 13F SOUTHWEST AIR COMMON STOCK 844741108 111,649 111,649 210.36 5,189 177.78 0.0530
2018-05-15 2018-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 0 -9,485 -100.00 0 -100.00
2018-03-29 2017-12-31 13F/A-1 SOUTHWEST AIR COMMON STOCK 844741108 9,485 -64,551 -87.19 621 -85.02 0.0261
2018-02-14 2017-12-31 13F SOUTHWEST AIR COMMON STOCK 844741108 9,485 -64,551 621
2017-11-13 2017-09-30 13F SOUTHWEST AIR COMMON STOCK 844741108 74,036 74,036 680.56 4,146 567.63 0.1927
2017-05-12 2017-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 0 -2,207,361 -100.00 0 -100.00
2017-02-10 2016-12-31 13F SOUTHWEST AIR COMMON STOCK 844741108 2,207,361 -70,649 -3.10 110,015 24.18 0.7233
2016-11-10 2016-09-30 13F SOUTHWEST AIR COMMON STOCK 844741108 2,278,010 891,763 64.33 88,592 62.99 0.6299
2016-08-12 2016-06-30 13F SOUTHWEST AIR COMMON STOCK 844741108 1,386,247 1,193,261 618.31 54,355 528.67 0.4570
2016-05-13 2016-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 192,986 -1,345,204 -87.45 8,646 -86.95 0.0833
2016-02-10 2015-12-31 13F SOUTHWEST AIR COMMON STOCK 844741108 1,538,190 -438,328 -22.18 66,234 -11.91 0.6215
2015-11-12 2015-09-30 13F SOUTHWEST AIR COMMON STOCK 844741108 1,976,518 1,769,515 854.83 75,186 997.61 0.9237
2015-08-14 2015-06-30 13F SOUTHWEST AIR COMMON STOCK 844741108 207,003 -63,749 -23.55 6,850 -42.89 0.0894
2015-05-11 2015-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 270,752 -467,088 -63.30 11,994 -61.59 0.1563
2015-02-17 2014-12-31 13F SOUTHWEST AIR COMMON STOCK 844741108 737,840 737,840 172.52 31,225 160.34 0.4122
2014-11-13 2014-09-30 13F SOUTHWEST AIR COMMON STOCK 844741108 0 -644,695 -100.00 0 -100.00
2014-08-14 2014-06-30 13F SOUTHWEST AIR COMMON STOCK 844741108 644,695 -241,182 -27.23 17,317 -17.21 0.2549
2014-05-14 2014-03-31 13F SOUTHWEST AIR COMMON STOCK 844741108 885,877 -1,617,987 -64.62 20,916 -35.19 0.3804
2013-08-06 2013-06-30 13F SOUTHWEST AIR COMMON STOCK 844741108 2,503,864 2,503,864 32,275 1.9317
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
(%)
2021-08-13 2021-06-30 13F June 21 Calls on LUV US at 62.5, American EQUITY OPTION Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-05-17 2021-03-31 13F June 21 Calls on LUV US at 62.5, American EQUITY OPTION Call 33,200 2,027 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
(%)
2026-02-13 2025-12-31 13F SOUTHWEST AIR EQUITY OPTION Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-11-13 2025-09-30 13F SOUTHWEST AIR EQUITY OPTION Put 90,000 2,872 n/a n/a n/a
2023-08-14 2023-06-30 13F SOUTHWEST AIR EQUITY OPTION Put 0 -100.00 0 -100.00 n/a n/a n/a
2023-05-15 2023-03-31 13F SOUTHWEST AIR EQUITY OPTION Put 78,000 2,538 n/a n/a n/a
2022-02-14 2021-12-31 13F October 21 Puts on LUV US at 50, American EQUITY OPTION Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-11-15 2021-09-30 13F October 21 Puts on LUV US at 50, American EQUITY OPTION Put 5,600 409.09 288 396.55 n/a n/a n/a
2021-08-13 2021-06-30 13F July 21 Puts on LUV US at 60, American EQUITY OPTION Put 1,100 -94.15 58 -94.95 n/a n/a n/a
2021-05-17 2021-03-31 13F May 21 Puts on LUV US at 57.5, American EQUITY OPTION Put 18,800 1,149 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.