How are SPDRs and MidCap SPDRs created and redeemed?
Most SPDR and MidCap SPDR holders buy and sell in the secondary trading market. But units are initially created when they are issued by the trusts to an investor who, after placing an order, deposits with the trustee a specified number of shares of index stocks and cash equal to accumulated dividends. While investors can trade any amount of SPDRs and MidCap SPDRs, they can only be created and redeemed from the trusts in “creation units” of 50,000 SPDRs and 25,000 MidCap SPDRs (or multiples thereof).