Ranking Codex 5.2 ahead of plain 5.2 doesn't make sense. Codex is expressly designed for coding tasks. Not systems design, not problem analysis, and definitely not banking, but actually solving specific programming tasks (and it's very, very good at this). GPT 5.2 (non-codex) is better in every other way.
Codex has been post-trained for coding, including agentic coding tasks.
It's certainly not impossible that the better long-horizon agentic performance in Codex overcomes any deficiencies in outright banking knowledge that Codex 5.2 has vs plain 5.2.
It could be problem specific. There are certain non program things that opus seems better than sonnet at as well
Swapped sonnet and opus on my last reply, oops