ETF (Exchange Traded Fund)
A fund comprised of a basket of equities (or other assets) that trades like a single stock.
SPY tracks the S&P 500. QQQ tracks the Nasdaq 100. GLD tracks gold. ETFs let you take one-click exposure to a whole market or sector. More relevant for retail investors than day traders, but liquid ETFs (SPY, QQQ) are actively traded.
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