The SPDR S&P 500 ETF (SPY) has seen a massive influx of $15 billion in assets, boosting overall weekly ETF inflows. This substantial haul for SPY has contributed to the strong performance of ETFs in recent days. Investors are showing a strong interest in ETFs, particularly those tied to the S&P 500 index. The $15 billion influx comes as no surprise, given the popularity of SPY among investors seeking exposure to large-cap U.S. stocks. This significant increase in assets demonstrates the continued appeal of ETFs as a preferred investment vehicle for many individuals.