Right Answer, Wrong Reasons: AI Forecasts Costco - Hassan El Mghari & Omar El Mghari, Together AI

Hassan El Mghari of Together AI and his father Omar, a former CFO and head of internal audit, test whether an open model can forecast a company's profits. They give GPT-OSS-120B only Costco's public filings from before its 2024 membership fee increase, have it write the financial model as structured formulas, and run 16 cheap attempts in parallel. The forecast lands within 4.4% of Costco's actual results, until an audit of the assumptions shows two errors that happened to cancel out. Their takeaway: when you build agents for specialized work, put an expert in the loop and turn their checks into code. Chapters: 0:00 Intro 0:30 Can an AI forecast Costco's profits? 0:49 Meet the father-son team 2:21 Spoiler: 4.4% off 3:03 Why membership fees matter to Costco 4:12 Using models that didn't already know the answer 5:03 Turning 214 filings into 3,000 facts 5:50 Have models write formulas, not do the math 7:18 Checks and 16 parallel runs 8:41 The forecast 9:53 An auditor looks at the assumptions 11:39 Two errors that canceled out 13:29 Three lines of defense 14:48 Put an expert in the loop Hassan El Mghari Omar El Mghari https://www.together.ai Join us in SF for the second annual AIE CODE summit: https://aie.codes our last flagship summit of 2026. Applications live now!