Mark Price
A fair-value estimate for an option, often based on the midpoint of bid and ask.
Explanation
Platforms use mark price for unrealized P&L, risk metrics, and portfolio valuation because last-trade prices can be stale. Mark may be midpoint-based or model-adjusted depending on venue. In wide markets, mark is informative but not guaranteed fillable.
Example
If bid is $1.90 and ask is $2.10, mark price is commonly shown as $2.00.