Hacker Severin
Director · Officer · Ten-percent owner · DUOL
As of 2026-09-16, Hacker Severin has 449 Form 4 transactions on record across 1 company — 86 in the trailing 12 months.
Everything this person has disclosed to the SEC on Form 4 — across every company they file for — reconstructed from the public record. A filing history, not a tip sheet.
Reconstructed holdings
Reconstructed from this person's own Form 4 filings — the total each filing reported owning afterward, priced at the close on the as-of date shown. A filed position can lag the real one.
Direct and indirect holdings (e.g. through a trust or fund) are tagged separately, as filed.
Trades by company
Filing ledger
| Date | Company | Action | Shares @ price | Value | Ownership Δ | Owned after | Filing |
|---|---|---|---|---|---|---|---|
| 2025-11-19 | DUOL | Sale | 3,089 @ $174.61 | $539K | −79.7% of holding | 787 | Form 4 |
| 2025-11-19 | DUOL | Sale | 2,009 @ $171.50 | $345K | −25.3% of holding | 5,917 | Form 4 |
| 2025-11-19 | DUOL | Sale | 1,281 @ $172.39 | $221K | −21.6% of holding | 4,636 | Form 4 |
| 2025-11-19 | DUOL | Sale | 1,146 @ $169.57 | $194K | −11.4% of holding | 8,926 | Form 4 |
| 2025-11-19 | DUOL | Sale | 1,000 @ $170.55 | $171K | −11.2% of holding | 7,926 | Form 4 |
| 2025-11-19 | DUOL | Sale | 760 @ $173.74 | $132K | −16.4% of holding | 3,876 | Form 4 |
| 2025-11-19 | DUOL | Sale | 435 @ $175.46 | $76K | −55.3% of holding | 352 | Form 4 |
| 2025-11-19 | DUOL | Sale | 280 @ $176.68 | $49K | −79.5% of holding | 72 | Form 4 |
| 2025-11-04 | DUOL | Sale | 1,778 @ $261.94 | $466K | −23.2% of holding | 5,889 | Form 4 |
| 2025-11-04 | DUOL | Sale | 1,727 @ $266.12 | $460K | −58.7% of holding | 1,217 | Form 4 |
| 2025-11-04 | DUOL | Sale | 1,625 @ $264.06 | $429K | −30.5% of holding | 3,704 | Form 4 |
| 2025-11-04 | DUOL | Sale | 1,145 @ $266.87 | $306K | −94.1% of holding | 72 | Form 4 |
| 2025-11-04 | DUOL | Sale | 936 @ $258.77 | $242K | −10.0% of holding | 8,392 | Form 4 |
| 2025-11-04 | DUOL | Sale | 760 @ $265.02 | $201K | −20.5% of holding | 2,944 | Form 4 |
| 2025-11-04 | DUOL | Sale | 744 @ $257.92 | $192K | −7.4% of holding | 9,328 | Form 4 |
| 2025-11-04 | DUOL | Sale | 560 @ $262.97 | $147K | −9.5% of holding | 5,329 | Form 4 |
| 2025-11-04 | DUOL | Sale | 560 @ $259.71 | $145K | −6.7% of holding | 7,832 | Form 4 |
| 2025-11-04 | DUOL | Sale | 165 @ $261.14 | $43K | −2.1% of holding | 7,667 | Form 4 |
| 2025-10-20 | DUOL | Sale | 1,600 @ $316.64 | $507K | −36.7% of holding | 2,759 | Form 4 |
| 2025-10-20 | DUOL | Sale | 1,281 @ $312.37 | $400K | −17.7% of holding | 5,959 | Form 4 |
| 2025-10-20 | DUOL | Sale | 1,100 @ $315.79 | $347K | −20.2% of holding | 4,359 | Form 4 |
| 2025-10-20 | DUOL | Sale | 1,000 @ $311.43 | $311K | −12.1% of holding | 7,240 | Form 4 |
| 2025-10-20 | DUOL | Sale | 907 @ $318.73 | $289K | −43.6% of holding | 1,172 | Form 4 |
| 2025-10-20 | DUOL | Sale | 680 @ $317.68 | $216K | −24.6% of holding | 2,079 | Form 4 |
| 2025-10-20 | DUOL | Sale | 632 @ $309.94 | $196K | −7.1% of holding | 8,240 | Form 4 |
| 2025-10-20 | DUOL | Sale | 600 @ $307.55 | $185K | −6.0% of holding | 9,372 | Form 4 |
| 2025-10-20 | DUOL | Sale | 500 @ $313.93 | $157K | −8.4% of holding | 5,459 | Form 4 |
| 2025-10-20 | DUOL | Sale | 500 @ $309.06 | $155K | −5.3% of holding | 8,872 | Form 4 |
| 2025-10-20 | DUOL | Sale | 400 @ $321.75 | $129K | −45.9% of holding | 472 | Form 4 |
| 2025-10-20 | DUOL | Sale | 300 @ $323.09 | $97K | −63.6% of holding | 172 | Form 4 |
| 2025-10-20 | DUOL | Sale | 300 @ $319.97 | $96K | −25.6% of holding | 872 | Form 4 |
| 2025-10-20 | DUOL | Sale | 100 @ $324.10 | $32K | −58.1% of holding | 72 | Form 4 |
| 2025-10-20 | DUOL | Sale | 100 @ $305.86 | $31K | −1.0% of holding | 9,972 | Form 4 |
| 2025-10-06 | DUOL | Sale | 1,916 @ $318.26 | $610K | −20.0% of holding | 7,656 | Form 4 |
| 2025-10-06 | DUOL | Sale | 1,803 @ $320.33 | $578K | −29.8% of holding | 4,254 | Form 4 |
| 2025-10-06 | DUOL | Sale | 1,599 @ $319.56 | $511K | −20.9% of holding | 6,057 | Form 4 |
| 2025-10-06 | DUOL | Sale | 1,300 @ $327.44 | $426K | −82.7% of holding | 272 | Form 4 |
| 2025-10-06 | DUOL | Sale | 1,173 @ $321.39 | $377K | −27.6% of holding | 3,081 | Form 4 |
| 2025-10-06 | DUOL | Sale | 600 @ $326.50 | $196K | −27.6% of holding | 1,572 | Form 4 |
| 2025-10-06 | DUOL | Sale | 500 @ $325.22 | $163K | −18.7% of holding | 2,172 | Form 4 |
| 2025-10-06 | DUOL | Sale | 500 @ $317.31 | $159K | −5.0% of holding | 9,572 | Form 4 |
| 2025-10-06 | DUOL | Sale | 300 @ $324.10 | $97K | −10.1% of holding | 2,672 | Form 4 |
| 2025-10-06 | DUOL | Sale | 200 @ $328.75 | $66K | −73.5% of holding | 72 | Form 4 |
| 2025-10-06 | DUOL | Sale | 109 @ $322.62 | $35K | −3.5% of holding | 2,972 | Form 4 |
| 2025-09-19 | DUOL | Sale | 2,300 @ $288.81 | $664K | −35.5% of holding | 4,172 | Form 4 |
| 2025-09-19 | DUOL | Sale | 2,300 @ $287.81 | $662K | −26.2% of holding | 6,472 | Form 4 |
| 2025-09-19 | DUOL | Sale | 2,200 @ $290.78 | $640K | −96.8% of holding | 72 | Form 4 |
| 2025-09-19 | DUOL | Sale | 1,900 @ $289.79 | $551K | −45.5% of holding | 2,272 | Form 4 |
| 2025-09-19 | DUOL | Sale | 1,300 @ $286.77 | $373K | −12.9% of holding | 8,772 | Form 4 |
| 2025-09-05 | DUOL | Sale | 2,100 @ $267.93 | $563K | −27.7% of holding | 5,475 | Form 4 |
| 2025-09-05 | DUOL | Sale | 1,956 @ $268.92 | $526K | −35.7% of holding | 3,519 | Form 4 |
| 2025-09-05 | DUOL | Sale | 1,647 @ $271.05 | $446K | −85.8% of holding | 272 | Form 4 |
| 2025-09-05 | DUOL | Sale | 1,600 @ $269.87 | $432K | −45.5% of holding | 1,919 | Form 4 |
| 2025-09-05 | DUOL | Sale | 1,148 @ $265.95 | $305K | −12.0% of holding | 8,424 | Form 4 |
| 2025-09-05 | DUOL | Sale | 849 @ $266.90 | $227K | −10.1% of holding | 7,575 | Form 4 |
| 2025-09-05 | DUOL | Sale | 500 @ $264.75 | $132K | −5.0% of holding | 9,572 | Form 4 |
| 2025-09-05 | DUOL | Sale | 200 @ $271.57 | $54K | −73.5% of holding | 72 | Form 4 |
| 2025-08-19 | DUOL | Sale | 1,979 @ $340.92 | $675K | −26.9% of holding | 5,390 | Form 4 |
| 2025-08-19 | DUOL | Sale | 1,700 @ $340.03 | $578K | −18.7% of holding | 7,369 | Form 4 |
| 2025-08-19 | DUOL | Sale | 1,318 @ $342.00 | $451K | −24.5% of holding | 4,072 | Form 4 |
| 2025-08-19 | DUOL | Sale | 1,003 @ $339.15 | $340K | −10.0% of holding | 9,069 | Form 4 |
| 2025-08-19 | DUOL | Sale | 600 @ $346.14 | $208K | −17.3% of holding | 2,872 | Form 4 |
| 2025-08-19 | DUOL | Sale | 500 @ $347.48 | $174K | −17.4% of holding | 2,372 | Form 4 |
| 2025-08-19 | DUOL | Sale | 400 @ $354.88 | $142K | −41.2% of holding | 572 | Form 4 |
| 2025-08-19 | DUOL | Sale | 400 @ $351.29 | $141K | −21.4% of holding | 1,472 | Form 4 |
| 2025-08-19 | DUOL | Sale | 400 @ $348.82 | $140K | −16.9% of holding | 1,972 | Form 4 |
| 2025-08-19 | DUOL | Sale | 300 @ $354.08 | $106K | −23.6% of holding | 972 | Form 4 |
| 2025-08-19 | DUOL | Sale | 300 @ $345.02 | $104K | −8.0% of holding | 3,472 | Form 4 |
| 2025-08-19 | DUOL | Sale | 300 @ $343.82 | $103K | −7.4% of holding | 3,772 | Form 4 |
| 2025-08-19 | DUOL | Sale | 200 @ $363.05 | $73K | −73.5% of holding | 72 | Form 4 |
| 2025-08-19 | DUOL | Sale | 200 @ $359.30 | $72K | −42.4% of holding | 272 | Form 4 |
| 2025-08-19 | DUOL | Sale | 200 @ $352.40 | $70K | −13.6% of holding | 1,272 | Form 4 |
| 2025-08-19 | DUOL | Sale | 100 @ $357.67 | $36K | −17.5% of holding | 472 | Form 4 |
| 2025-08-19 | DUOL | Sale | 100 @ $349.28 | $35K | −5.1% of holding | 1,872 | Form 4 |
| 2025-08-05 | DUOL | Sale | 2,205 @ $342.56 | $755K | −35.3% of holding | 4,036 | Form 4 |
| 2025-08-05 | DUOL | Sale | 2,098 @ $340.28 | $714K | −21.7% of holding | 7,571 | Form 4 |
| 2025-08-05 | DUOL | Sale | 1,330 @ $341.55 | $454K | −17.6% of holding | 6,241 | Form 4 |
| 2025-08-05 | DUOL | Sale | 1,133 @ $344.99 | $391K | −33.0% of holding | 2,303 | Form 4 |
| 2025-08-05 | DUOL | Sale | 931 @ $354.45 | $330K | −66.4% of holding | 472 | Form 4 |
| 2025-08-05 | DUOL | Sale | 600 @ $343.43 | $206K | −14.9% of holding | 3,436 | Form 4 |
137 award / exercise / gift records — not counted as purchases
| Date | Company | Action | Shares | Owned after | Filing |
|---|---|---|---|---|---|
| 2026-05-27 | DUOL | Withheld for tax | 31,920 | 205,273 | Form 4 |
| 2026-05-27 | DUOL | Option exercise | 60,000 | 237,193 | Form 4 |
| 2026-05-27 | DUOL | Option exercise | 60,000 | 210,000 | Form 4 |
| 2026-02-17 | DUOL | Withheld for tax | 30,594 | 177,193 | Form 4 |
| 2026-02-17 | DUOL | Option exercise | 60,000 | 270,000 | Form 4 |
| 2026-02-17 | DUOL | Option exercise | 60,000 | 207,787 | Form 4 |
| 2025-12-08 | DUOL | Conversion | 50,000 | 50,072 | Form 4 |
| 2025-12-08 | DUOL | Conversion | 50,000 | 2,836,917 | Form 4 |
| 2025-12-08 | DUOL | Gift | 50,000 | 72 | Form 4 |
| 2025-12-03 | DUOL | Option exercise | 5,252 | 147,787 | Form 4 |
| 2025-12-03 | DUOL | Option exercise | 5,252 | 0 | Form 4 |
| 2025-12-01 | DUOL | Withheld for tax | 31,770 | 142,535 | Form 4 |
| 2025-12-01 | DUOL | Option exercise | 60,000 | 330,000 | Form 4 |
| 2025-12-01 | DUOL | Option exercise | 60,000 | 174,305 | Form 4 |
| 2025-11-19 | DUOL | Conversion | 10,000 | 10,072 | Form 4 |
| 2025-11-19 | DUOL | Conversion | 10,000 | 114,305 | Form 4 |
| 2025-11-19 | DUOL | Conversion | 10,000 | 124,305 | Form 4 |
| 2025-11-19 | DUOL | Option exercise | 10,000 | 5,252 | Form 4 |
| 2025-11-04 | DUOL | Conversion | 10,000 | 10,072 | Form 4 |
| 2025-11-04 | DUOL | Option exercise | 10,000 | 15,252 | Form 4 |
| 2025-11-04 | DUOL | Conversion | 10,000 | 114,305 | Form 4 |
| 2025-11-04 | DUOL | Conversion | 10,000 | 124,305 | Form 4 |
| 2025-10-20 | DUOL | Withheld for tax | 31,770 | 114,305 | Form 4 |
| 2025-10-20 | DUOL | Conversion | 10,000 | 10,072 | Form 4 |
| 2025-10-20 | DUOL | Conversion | 10,000 | 86,075 | Form 4 |
| 2025-10-20 | DUOL | Option exercise | 10,000 | 25,252 | Form 4 |
| 2025-10-20 | DUOL | Conversion | 10,000 | 96,075 | Form 4 |
| 2025-10-20 | DUOL | Option exercise | 60,000 | 390,000 | Form 4 |
| 2025-10-20 | DUOL | Option exercise | 60,000 | 146,075 | Form 4 |
| 2025-10-06 | DUOL | Conversion | 10,000 | 10,072 | Form 4 |
| 2025-10-06 | DUOL | Conversion | 10,000 | 96,075 | Form 4 |
| 2025-10-06 | DUOL | Conversion | 10,000 | 86,075 | Form 4 |
| 2025-10-06 | DUOL | Option exercise | 10,000 | 35,252 | Form 4 |
| 2025-09-19 | DUOL | Conversion | 10,000 | 10,072 | Form 4 |
| 2025-09-19 | DUOL | Conversion | 10,000 | 96,075 | Form 4 |
| 2025-09-19 | DUOL | Conversion | 10,000 | 86,075 | Form 4 |
| 2025-09-19 | DUOL | Option exercise | 10,000 | 45,252 | Form 4 |
| 2025-09-05 | DUOL | Conversion | 10,000 | 10,072 | Form 4 |
| 2025-09-05 | DUOL | Option exercise | 10,000 | 55,252 | Form 4 |
| 2025-09-05 | DUOL | Conversion | 10,000 | 96,075 | Form 4 |
Source: SEC Form 4 filings. Each row links to its original filing.
Research tool, not investment advice — historical frequencies, not recommendations. A product of Marovel Technologies LLC. Full terms.