A call option gives the holder the right to buy a fund at a set price (the strike) before expiry; a put gives the right to sell. Traders buy calls to bet on, or position for, a rise, and buy puts to hedge or position for a fall. The put/call ratio compares the two.
InflowScan shows two versions for each ETF with a liquid options market. The open-interest ratio divides all open put contracts by all open call contracts — a slow-moving picture of how positions are stacked. The volume ratio uses the contracts traded in a single session, so it reacts faster to the day’s news.
The ratio describes positioning, not intent. A high ratio can mean bearish bets, but it often reflects holders of the fund buying protection while staying long. On thin option chains a few trades can swing the ratio wildly, so InflowScan only shows it once a fund has at least 5,000 contracts open.