This episode from "Quant Investing for Beginners" explains the foundational principles of quantitative investing, distinguishing it from quantitative trading by focusing on long-term wealth accumulation rather than short-term trading strategies. The core strategy presented involves diversifying an equity portfolio to reduce both idiosyncratic risk (firm-specific) and industry risk (sector-specific), leaving the investor primarily exposed to Market risk to capture positive market drift over time. The discussion emphasizes that achieving this diversification requires careful consideration of asset correlation, noting that these correlations are time-variant and non-constant, which necessitates rebalancing the portfolio to maintain the desired risk profile. Ultimately, the goal is to mitigate unnecessary risk while maintaining exposure to potential market returns, though this strategy does not guarantee profits