A large options block trade in iShares Silver Trust (SLV) made last week could be what is known as a collar trade. SLV is the most popular ETF for trading silver and is generally very active when it comes to options. Two very large blocks of puts and calls traded tied to stock (expiring in 2025) in what appears to be a protective collar spread. This type of trade generally caps the upside potential in the underlying stock in return for collecting premium, while also hedging downside risk.