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Style Performance by Calendar Month

Steve LeCompte | | Posted in: Calendar Effects, Size Effect, Value Premium

Key Insight

Style ETFs show modest monthly return differences versus SPY, with value outperforming growth in Mar/Apr/Dec and growth leading in Oct/Nov (Aug 2001–Oct 2021; 20-year sample too short for confident inference).

Trading Calendar presents full-year and monthly cumulative performance profiles for the overall stock market (S&P 500 Index) based on its average daily behavior. How much do the corresponding monthly behaviors of the various size and value/growth styles deviate from an overall equity market profile? To investigate, we consider the the following six exchange-traded funds (ETF) that cut across capitalization (large, medium and small) and value versus growth:

iShares Russell 1000 Value Index (IWD) - large capitalization value stocks.
iShares Russell 1000 Growth Index (IWF) - large capitalization growth stocks.
iShares Russell Midcap Value Index (IWS) - mid-capitalization value stocks.
iShares Russell Midcap Growth Index (IWP) - mid-capitalization growth stocks.
iShares Russell 2000 Value Index (IWN) - small capitalization value stocks.
iShares Russell 2000 Growth Index (IWO) - small capitalization growth stocks.

Using monthly dividend-adjusted closing prices for the style ETFs and SPDR S&P 500 (SPY) during August 2001 through June 2026 (limited by data for IWS/IWP), we find that:

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