M-19 is a thrash metal band from Porto Alegre, Rio Grande do Sul, Brazil, originally formed in 1989, drawing influence from Slayer, Destruction, Kreator, and Sepultura. After releasing demo tapes "Manifest of Insanity" (1989) and "When a Promise Is Broken" (1994) and a decade-long hiatus, the band returned to release the full-length "Mission: Destroy" in 2013 and "Sic Semper Tyrannis" in 2019, the latter celebrating thirty years of their founding.

Machinaria were a heavy/thrash metal band from Bagé, Rio Grande do Sul, Brazil. Their 2014 debut full-length Sacred Revolutions, Profane Revelations drew comparisons to second-wave American thrash acts such as Sacred Reich and Vio-Lence, and was built around a conceptual examination of the Catholic Inquisition. The album earned the band recognition as a standout name in the new generation of Brazilian thrash.

Madhouse is a thrash metal band from Rancagua, in Chile's O'Higgins Region, formed in 2019. The band operates independently within the active Chilean thrash metal underground, drawing on the aggressive traditions of the genre.

Madkill is an old-school thrash metal band from São Paulo, Brazil, formed in 2014 and rooted in the aggressive speed and thrash traditions of the Brazilian scene. The band released their debut album "Mass Destruction" in 2014 and followed it with "Intense Violence" in 2019, a ten-track record described as old school thrash/speed metal with tracks such as "Thrash City" and "Saint Death". They have remained active into the mid-2020s, releasing the politically charged "Protesto" in 2024.

Malaria is a thrash metal and crossover band from Merlo, Buenos Aires, operating in the tradition of aggressive street-level metal with lyrical themes spanning war, social commentary, and the mosh pit. The band has self-released multiple recordings on Bandcamp, including a three-track demo (2016), the eight-track "Future Decimation EP" (2017), and the two-track "Piss Tape" (2018).

Maleficio was a heavy/thrash metal band from San Fernando del Valle de Catamarca, Argentina, with a self-titled demo tape among their documented releases and a confirmed album entry "Go to Hell" listed on the Metal Archives. The band centred their lyrical themes on social denouncement and has since split up.

Malevolence was a São Paulo thrash metal band that carried the torch of the classic Brazilian style with aggressive riffing and a no-frills attitude toward speed and aggression. Active through the mid-2010s, the band was part of a new generation revisiting the raw thrash fundamentals that first put the city on the extreme metal map.

Malicia is a Buenos Aires thrash metal band formed in 1995 by vocalist and guitarist Maximiliano Escobar, who built the group around a core lineup that later solidified with guitarist Lucas Bravo, bassist Pablo Maldonado, and drummer Cristian Romero. Over two decades the band has released seven studio albums, including Agresivo (2004), El fin de las religiones (2012), and Neuromuerte (2016), earning a reputation as one of the more prolific acts in the Argentine thrash scene.

Malinche is a thrash and hardcore crossover band from Paraná, Entre Ríos, Argentina, featuring vocalist José "El Ruso" Argento, guitarist Miguel Heltner, bassist Gabriel Blanco, and drummer Manuel Larrea. The band released their debut album Nuevo Orden Vol.1 in 2016, preceded by the single "El Demoledor" as an advance track, and have contributed material to the Paraná Bandas regional compilation platform.