mdy

MDY is an acronym that can refer to multiple concepts depending on context. In date notation, MDY stands for Month-Day-Year, the conventional order used in the United States for writing calendar dates. In this order, dates are written with the month first, followed by the day and the year (for example, 04/07/2025). The MDY format is common in the U.S. but can create ambiguity when data is exchanged internationally, since other regions use Day-Month-Year or Year-Month-Day. To avoid misinterpretation, software and documents often specify the exact format or use four-digit years.

In finance, MDY is the ticker symbol for the SPDR S&P MidCap 400 ETF Trust. This exchange-traded fund, administered by State Street Global Advisors, seeks to track the performance of the S&P MidCap 400 Index. The fund provides exposure to U.S. mid-cap stocks and is traded on major exchanges. Its objective is to match, before fees and expenses, the price and yield performance of the underlying index. Investors use MDY for mid-cap exposure, liquidity, and as part of diversified portfolios.