Traders' net delta

Also called Net delta, delta dollars, delta notional, net delta bought

The delta traders bought minus sold over a session, in dollars of the underlying: + is upside exposure added.

Traders' net delta is the delta of the options traders bought minus those they sold, in dollars:

delta $ = Σ delta × 100 × price × (contracts bought − contracts sold)

+$500M means traders took on as much upside exposure as $500M of the stock: buying calls and selling puts both add it. −$500M is the same size the other way: calls sold or puts bought.

Delta in dollars lets one name be set beside another: 1,000 SPX contracts and 1,000 contracts of a $20 stock aren't the same bet, and their dollars say how different.

In Theta Vantage

Traders' net greeks (Pro) gives each session's net delta for the 50 names with the most option volume, calls and puts apart, beside gamma and vega. It's estimated from each trade's side. The dealers' own delta is a different figure: dealer delta exposure.