Capital Markets
Capital markets engineering is the software behind buying and selling securities: order routing and matching, market data feeds, and the clearing and settlement plumbing that turns a fill into ownership. It is a narrow field that pays for depth.
Assumes you know: Comfortable with concurrency, queues and networking fundamentals, Able to read a binary or delimited wire protocol specification
Overview
What this area actually covers
Capital markets software moves an instruction to buy or sell a security through to a record of ownership. That span is the whole subject. A portfolio manager or an algorithm decides to buy; a broker's order management system validates and routes the order; a venue matches it against a willing seller; the trade is confirmed, cleared, and settled when cash moves one way and the security the other. Every system you will be asked about sits on that line, and a good candidate says which part they built.
Two things get wrongly bundled in. Retail payments share vocabulary with settlement but have different regulators and failure modes. Quantitative research consumes the same data, but the skill is mathematical, and nobody hiring a trading systems engineer is testing your stochastic calculus.
A third confusion is worth naming early because it shapes how you read job adverts. "Trading systems" in common speech means the fast part at the front, but the great majority of employment in this domain is behind that: order management, enrichment, risk, allocation, confirmation, settlement instruction, reconciliation, reporting. The front end is where the vocabulary comes from. The back is where the headcount is.
Where to go next
Now practise it
20 interview questions in Capital Markets, each with the rubric the interviewer is scoring against.
- A dividend is declared and half the client's holding is out on loan while part of the rest is pledged as collateral. Who receives the income, who votes, and what does your system show the client?
- A payment instruction is about to leave your firm that is a hundred times the usual size for that counterparty. What in your systems should stop it, and who should be looking at it?
- The clearing house has called far more initial margin than your own risk system predicted. How do you find out why before the deadline?
- You need one consolidated best bid and offer across five venues whose feeds arrive at different latencies. How do you build it, and what will it get wrong?