Reading up on fintech

Hacker News commenters debate whether monetary values must always be stored as integers, with quants arguing floats suffice for risk modeling but transfers require exact integer precision.

The handbook catalogs patterns for representing, recording, and executing money movements—precision handling, double-entry ledgers, immutability, and invariants—to prevent data loss or invention in fintech systems.

OpenAI launches personal finance tools for ChatGPT Pro users, letting them connect bank accounts via Plaid for spending analysis and planning.

Ramp introduces Agent Cards, a CLI tool that enables agents to access and interact with structured card-based information.

Agentic commerce will shift from retail payment rails to pre-negotiated B2B credit and stablecoins, as agents behave like local businesses with long-term vendor relationships.

Capital One acquires fintech Brex for $5.15 billion, a significant discount from its $12.3 billion peak valuation in 2022.

Capital One will acquire fintech Brex for $5.15 billion in cash and stock to gain its corporate credit-card and expense-management technology.

Brex's CTO describes how a 10-person AI team, agentic coding adoption, and company-wide AI fluency training fueled a turnaround to $500M+ ARR.

Robinhood and Susquehanna are launching a new futures and derivatives exchange to expand prediction contracts offerings tied to sports, elections, and other events.