Founder Directory
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Founders2
Known for these resultsRole100%Role is parsed from founder titles in yc.db. Known for 100% of these rows — the rest have no title at all, mostly 2019–2023. Those rows stay in the result and are counted as Unknown, never as No.Bio100%Bio coverage: 100% of these founders have a bio on their YC profile. Every bio-derived facet (ex-company, school, credentials, discipline) is Unknown for the rest.Ex-company50%Ex-company is matched from bios with employment context (ex-, formerly, worked at). 50% of these rows have at least one match.School0%School is matched from bios, case-sensitive for acronyms. 0% of these rows have at least one match.
- Jackson StokesFounder/CEO · TrainLoopW25B2B · San Francisco
- Mason Pierce@mlpierce22Founder/CTO · TrainLoopW25B2B · San Francisco
FOUNDERROLEBATCHINDUSTRYLOCATIONTEAMX_url
Jackson StokesTrainLoopFounder/CEOWinter 2025B2BSan Francisco, United States6—Mason PierceTrainLoopFounder/CTOWinter 2025B2BSan Francisco, United States6https://x.com/mlpierce22
Showing 1–2 of 2 founders
Mason Pierce
Founder/CTO·TrainLoop
PRIMARY INFO
RoleFounder/CTO
Team size6
BatchWinter 2025
LocationSan Francisco, United States
Company statusActive
StageEarly
BIO
My background is in applying AI models to business use-cases and have always found fine-tuning to be way harder than it should be - My mission is to unlock fine-tuning for all builders :)
Ex-company, school and discipline below are derived from this bio. Nothing is inferred when the bio is missing.
BACKGROUND
No notable employer or school mentioned in the bio.
Credentialsnone mentioned
Disciplinenot detectedKeyword match from the bio text, not a classifier.
TRACK RECORD
First YC company on record
COMPANY CONTEXT
TrainLoopReasoning Fine-Tuning
Co-foundersJackson Stokes
