The stock perp books carry two kinds of equity market. Index perps follow the S&P 500 and the Nasdaq 100. Single-name perps follow one company each, such as NVDA, TSLA, AAPL, MSFT, AMZN, GOOGL, META and MU. They share every mechanic: mark, oracle, premium, funding, open interest. What differs is what sits underneath, and that changes how each should be read.

What moves each

An index is an average of many companies. News about one member is diluted by all the rest. An index perp moves mostly on things that touch everything at once: rates, economic data, broad risk appetite.

A single stock has no such cushion. An earnings report, a product announcement or a legal ruling lands on it in full. A single-name perp can move several times as far as the index on the same day, in either direction. With leverage, that changes how close a liquidation level is.

Depth

The index perps are among the largest of these markets. On 4 October 2026 the S&P 500 perp held about $349 million of open interest. The Nasdaq 100 perp held about $247 million. Single-name markets range from large to very small. A print on a deep market carries more weight than the same print on a shallow one, so check open interest before reading a move on any single name.

Hours and the reference

Both kinds trade around the clock, weekends included. Both follow a reference that is quiet when the stock market is shut. In those hours the perp’s own price is doing the work, a point taken up in a stock perp when the cash market is closed.

Reading them as a pair

An index move is made of its members’ moves, and a few large members carry much of the weight. Reading the largest single-name perps beside the index perp shows what is behind an index move. If the index perp is up and one name explains most of it, that is a narrow move. If the largest names are all up together, it is broad. Mega-cap perps and the index move goes further.

The two can also disagree. A flat index perp with one mega-cap sharply lower means the rest of the index is offsetting it, and the single name has its own story.

What has no perp

Coverage has a hard edge. No liquid perp exists on the Russell 2000 or on IWM. There is no small-cap perp to read. Using the S&P 500 perp as a stand-in for small caps would be inventing a figure.

Where NoVo shows them

On Trader, the Perps & Futures tab shows the index perps, the mega-cap perps and the largest other perps. While the cash market is shut it shows each index perp’s move since the last close, measured as in the implied open.