What is market data?
Dynamic financial data such as prices, quotes, trades, volumes, order book updates, yields, and implied volatilities.
What is reference data?
Instrument metadata such as ticker, ISIN, exchange, currency, lot size, and trading calendar.
What is a security master?
A centralized system or dataset used to maintain canonical instrument identities and metadata.
Why is a security master important?
It ensures the same instrument is recognized consistently across research, trading, risk, and operations.
What is symbology in finance?
The identifiers used to refer to instruments, such as ticker, ISIN, CUSIP, or SEDOL.
Why is symbology hard in finance?
Different vendors and systems may use different identifiers or represent instruments differently.
What is corporate actions data?
Data describing events like dividends, splits, mergers, and spin-offs that affect instruments and positions.
Why is corporate actions handling a hard data problem?
It changes positions, pricing histories, entitlements, and instrument relationships over time.
What is event time?
The time an event actually occurred in the market.
What is processing time?
The time a system received or processed the event.
Why does event time matter?
Accurate sequencing and backtesting require the true market-time ordering of events.
What is out-of-order data?
Events arriving in a different order than they occurred.
What is late data?
Events that arrive after the time they should ideally have been processed.
What is a corrected trade or cancel/correct message?
A message that changes or reverses a previously reported trade.
What is survivorship bias in market data?
The error of only analyzing securities that still exist and ignoring delisted or failed ones.
What is look-ahead bias?
Using information in a backtest that would not have been known at the time.
Why are survivorship bias and look-ahead bias dangerous?
They make historical performance look unrealistically good.
What is a feature store in a quant or AI context?
A managed repository of reusable model features with consistent definitions and lineage.
Why is lineage important in financial data platforms?
It helps trace where data came from, how it was transformed, and whether it is trustworthy.
What is data provenance?
The documented origin and history of a dataset.
Why is auditability important in finance?
Systems often need to explain how outputs were produced for risk, compliance, and operational review.
What is a data quality check in market data?
A rule that detects missing, stale, outlier, duplicated, or inconsistent data.
What is stale data?
Data that has not updated when it should have.
What is a market calendar?
The schedule of trading days, holidays, and session times for a venue or market.
