Price indices
How the index price and the mark price are built, and why a single trade barely moves them.
Index price
The index price is a weighted median of spot prices from several major exchanges and on-chain price feeds. A median ignores outliers, so one source printing a bad price does not move it.
Mark price
The mark price is a weighted combination of several sources: spot and perpetual prices from major exchanges, on-chain price feeds, and Titan's own order book, smoothed over time.
It is what Titan uses for margin, unrealised profit and loss, liquidation, and take profit and stop loss triggers. Because it blends several sources and moves gradually, a single trade on Titan's book barely moves it.