{"cik":"0001914625","entityType":"other","sic":"5990","sicDescription":"Retail-Retail Stores, NEC","ownerOrg":"07 Trade & Services","insiderTransactionForOwnerExists":0,"insiderTransactionForIssuerExists":0,"name":"Masterworks 121, LLC","tickers":[],"exchanges":[],"ein":"880849911","lei":null,"description":"","website":"","investorWebsite":"","category":"","fiscalYearEnd":"1231","stateOfIncorporation":"DE","stateOfIncorporationDescription":"DE","addresses":{"mailing":{"street1":"1 WORLD TRADE CENTER","street2":"57TH FLOOR","city":"NEW YORK","stateOrCountry":"NY","zipCode":"10007","stateOrCountryDescription":"NY","isForeignLocation":0,"foreignStateTerritory":null,"country":null,"countryCode":null},"business":{"street1":"1 WORLD TRADE CENTER","street2":"57TH FLOOR","city":"NEW YORK","stateOrCountry":"NY","zipCode":"10007","stateOrCountryDescription":"NY","isForeignLocation":null,"foreignStateTerritory":null,"country":null,"countryCode":null}},"phone":"2035185172","flags":"","formerNames":[],"filings":{"recent":{"accessionNumber":["0001493152-26-030729","0001493152-26-025972","0001493152-26-020263","0001493152-26-017406","0001493152-26-001497","0001493152-25-022815","0001493152-25-015288","0001641172-25-019169","0001641172-25-007180","0001641172-25-004494","0001493152-25-000816","0001493152-24-051611","0001493152-24-039939","0001493152-24-036812","0001493152-24-027478","0001493152-24-016355","0001493152-24-013680","0001493152-24-001529","0001493152-24-000895","0001493152-23-035969","0001493152-23-035569","0001493152-23-034227","0001493152-23-031016","0001493152-23-023756","0001493152-23-014387","0001493152-23-011506","0001493152-23-009427","0001493152-22-037025","0001493152-22-036936","0001493152-22-025950","0001493152-22-024742","0001493152-22-020787","0001493152-22-017300","9999999994-22-000208","0001493152-22-016198","0000000000-22-004994","0001493152-22-011935"],"filingDate":["2026-06-29","2026-05-29","2026-04-30","2026-04-17","2026-01-12","2025-11-14","2025-09-26","2025-07-14","2025-04-30","2025-04-14","2025-01-06","2024-12-23","2024-10-07","2024-09-17","2024-07-15","2024-04-26","2024-04-08","2024-01-05","2024-01-04","2023-10-05","2023-10-04","2023-09-27","2023-08-31","2023-07-06","2023-04-28","2023-04-07","2023-03-29","2022-12-30","2022-12-30","2022-09-15","2022-08-31","2022-07-29","2022-06-21","2022-06-09","2022-06-08","2022-05-06","2022-05-03"],"reportDate":["","2026-05-29","2025-12-31","2026-04-17","2026-01-12","2025-11-14","2025-06-30","2025-07-14","2024-12-31","2025-04-14","2025-01-06","2024-12-23","2024-10-07","2024-06-30","2024-07-15","2023-12-31","2024-04-08","2024-01-05","2024-01-04","2023-10-05","2023-10-04","2023-06-30","2023-08-31","2023-07-06","2022-12-31","2023-04-07","2023-03-29","2022-12-30","","2022-09-15","2022-06-30","2022-07-29","","","","",""],"acceptanceDateTime":["2026-06-29T16:41:45.000Z","2026-05-29T14:17:23.000Z","2026-04-30T19:43:13.000Z","2026-04-17T15:04:02.000Z","2026-01-12T19:11:20.000Z","2025-11-14T15:13:52.000Z","2025-09-26T14:53:58.000Z","2025-07-14T17:59:44.000Z","2025-04-30T17:15:55.000Z","2025-04-14T19:05:35.000Z","2025-01-06T17:57:45.000Z","2024-12-23T20:09:29.000Z","2024-10-07T18:09:49.000Z","2024-09-17T15:47:21.000Z","2024-07-15T15:53:52.000Z","2024-04-26T19:34:02.000Z","2024-04-08T18:16:45.000Z","2024-01-05T21:57:10.000Z","2024-01-04T16:17:45.000Z","2023-10-05T16:06:28.000Z","2023-10-04T14:46:55.000Z","2023-09-27T15:30:52.000Z","2023-08-31T19:27:53.000Z","2023-07-06T18:38:32.000Z","2023-04-28T16:52:07.000Z","2023-04-07T16:57:24.000Z","2023-03-29T19:42:49.000Z","2022-12-30T19:19:56.000Z","2022-12-30T18:26:13.000Z","2022-09-15T15:25:51.000Z","2022-08-31T21:22:20.000Z","2022-07-29T21:21:15.000Z","2022-06-21T14:49:28.000Z","2022-06-10T04:15:08.000Z","2022-06-08T21:06:19.000Z","2022-05-06T15:30:03.000Z","2022-05-03T20:25:36.000Z"],"act":["33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","33","","","33"],"form":["1-Z","1-U","1-K","1-U","1-U","1-U","1-SA","1-U","1-K","1-U","1-U","1-U","1-U","1-SA","1-U","1-K","1-U","1-U","1-U","1-U","1-U","1-SA","1-U","1-U","1-K","1-U","1-U","1-U","253G2","1-U","1-SA","1-U","253G2","QUALIF","CORRESP","UPLOAD","1-A"],"fileNumber":["24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","24R-00644","024-11875","24R-00644","24R-00644","24R-00644","024-11875","024-11875","","","024-11875"],"filmNumber":["261133705","261039976","26924408","26870218","26526076","251482181","251346890","251121144","25893243","25835725","25510112","241572779","241357254","241303185","241116395","24883064","24829145","24517014","24510420","231310441","231306949","231283101","231228731","231073211","23863150","23808381","23774947","221501542","221501325","221245050","221218831","221121913","221026563","221007522","","","22887347"],"items":["","9.1","","9.1","9.1","9.1","","9.1","","9.1","9.1","9.1","9.1","","9.1","","9.1","9.1","9.1","9.1","9.1","","9.1","9.1","","9.1","9.1","9.1","","9.1","","9.1","","","","",""],"core_type":["1-Z","1-U","1-K","1-U","1-U","1-U","1-SA","1-U","1-K","1-U","1-U","1-U","1-U","1-SA","1-U","1-K","1-U","1-U","1-U","1-U","1-U","1-SA","1-U","1-U","1-K","1-U","1-U","1-U","253G2","1-U","1-SA","1-U","253G2","QUALIF","CORRESP","LETTER","1-A"],"size":[2727,22600,326273,31132,31203,31379,200613,31559,335348,32535,29517,25646,31441,355374,30106,350489,28313,29398,808826,24300,30383,201929,24979,30304,351796,30478,24413,260188,110178,654129,194976,2619959,1412860,1700,20378,40924,15171482],"isXBRL":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],"isInlineXBRL":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],"isXBRLNumeric":[0,0,0,0,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null],"primaryDocument":["xsl1-Z_X01/primary_doc.xml","form1-u.htm","xsl1-K_X01/primary_doc.xml","form1-u.htm","form1-u.htm","form1-u.htm","form1-sa.htm","form1-u.htm","xsl1-K_X01/primary_doc.xml","form1-u.htm","form1-u.htm","form1-u.htm","form1-u.htm","form1-sa.htm","form1-u.htm","xsl1-K_X01/primary_doc.xml","form1-u.htm","form1-u.htm","form1-u.htm","form1-u.htm","form1-u.htm","form1-sa.htm","form1-u.htm","form1-u.htm","xsl1-K_X01/primary_doc.xml","form1-u.htm","form1-u.htm","form1-u.htm","form253g2.htm","form1-u.htm","form1-sa.htm","form1-u.htm","form253g2.htm","xslQUALIFX01/primary_doc.xml","filename1.htm","filename1.pdf","xsl1-A_X01/primary_doc.xml"],"primaryDocDescription":["","1-U","","1-U","1-U","1-U","1-SA","1-U","","","","","","","","","","","","","","","","","","","","","","","","","","","","",""]},"files":[]}}