Evidence update · posts October 16

Spark Open tops US open models on Signal65; it's unaudited

Meta's Muse Spark Open ranks first among US open-weight models on Signal65's agent-task leaderboard, and 13th among open models on Arena.ai's web-development board; neither board puts Muse Spark Open first among open-weight models worldwide. On the web-development board of Arena.ai, a crowd-voted leaderboard, Muse Spark Open scores 1511 and ranks 13th among open models (Arena.ai, 2026-10-16). On PINNACLE, the agent leaderboard from the measurement firm Signal65 that ranks models on multi-step enterprise tasks, Muse Spark Open is first of 16 US open-weight models and fourth of 35 open-weight models overall. The top three are two of Alibaba's Qwen3.8 models and DeepSeek-V4.1-Flash (Signal65, 2026-10-16). The October 16 issue reported that Spark Open had no independent evaluation on release day; these are two leaderboard readings since then. Neither board is audited, and Arena.ai doesn't state the population of US open-weight models. Signal65 belongs to industry analyst Patrick Moorhead's group, which does business with vendor clients. How we checked →

Concept illustration: a person with long dark hair, dressed in black with a badge on a lanyard, stands in the circular opening at the centre of a round beige counter, looking down at a clipboard. In the left foreground is a large red laptop whose lid shows a blue looped symbol with the word META and, on a black band, MUSE SPARK OPEN; behind the person sits an open grey laptop whose screen shows three windows (an envelope, a grid and rows of lines), a partly visible grey laptop sits at the far left edge, and on the right stands a white upright sign lettered QWEN3.8 above an orange swirl symbol and ALIBABA, against pale walls and a beige pillar.

Source and checks

This item ran in the brief of Oct 17, 2026, alongside 15 other items. How we checked it, the quote checks and what was still missing that day are on that issue's How we checked page.

Cite this item

SecondSource (2026). "Spark Open tops US open models on Signal65; it's unaudited." https://secondsource.io/en/research/2026-10-17-2/. Accessed access date.