I've got no source for you, sorry. If you find an earlier passively managed value fund please share it.
You shouldn't need a source to know that all funds from 1937 to the 1970s were actively managed, (i.e. they were not tracking a value index. )
Since the first Passive fund of any kind (The Vanguard 500 fund) did not even exist until 1970s, it is literally impossible that a value fund from 1937-1970 could be passively managed.
Looking at RZV, the prospectus is very clear:
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INVESTMENT OBJECTIVE
The investment objective of the Guggenheim S&P SmallCap 600® Pure Value ETF (the “Fund”) is to replicate as closely as possible, before fees and expenses, the performance of the S&P SmallCap 600® Pure Value Index Total Return (the “Underlying Index”).
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The prospectus for DFSVX doesn't have any wording like this at all. Here's the relevant piece, I understand how RZV can be defined as passively managed, but how does that fit here?
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Principal Investment Strategies
U.S. Small Cap Value Portfolio, using a market capitalization weighted approach, purchases a broad and diverse group of the readily marketable securities of
U.S. small cap companies that Dimensional Fund Advisors LP (the “Advisor”) determines to be value stocks. A company’s market capitalization is the number of its shares outstanding times its price per share. In general, the higher the relative market capitalization of the U.S. small cap company, the greater its representation in the Portfolio. The Advisor may modify market capitalization weights and even exclude companies after considering such factors as free float, momentum, trading strategies, liquidity management, and profitability, as well as other factors that the Advisor determines to be appropriate, given market conditions.
Securities are considered value stocks primarily because a company’s shares have a high book value in relation to their market value. In assessing profitability, the Advisor may consider different ratios, such as that of earnings or profits from operations relative to book value or assets. As a non-fundamental policy, under normal circumstances, the U.S. Small Cap Value Portfolio will invest at least 80% of its net assets in securities of small cap U.S. companies.
As of the date of this Prospectus, for purposes of the U.S. Small Cap Value Portfolio, the Advisor considers small cap companies to be companies whose market capitalizations are generally in the lowest 10% of total market capitalization or companies whose market capitalizations are smaller than the 1,000th largest U.S. company, whichever results in the higher market capitalization break. Total market capitalization is based on the market capitalization of U.S. operating companies listed on the New York Stock Exchange (“NYSE”), NYSE MKT LLC, Nasdaq Global Market® or such other securities exchanges deemed appropriate by the Advisor. Under the Advisor’s market capitalization guidelines described above, as of December 31, 2014, the market capitalization of a small cap company was $3,938 million or below. This dollar amount will change due to market conditions.
The U.S. Small Cap Value Portfolio may use derivatives, such as futures contracts and options on futures contracts for U.S. equity securities and indices, to adjust market exposure based on actual or expected cash inflows to or outflows from the Portfolio. The Portfolio does not intend to use derivatives for purposes of speculation or leveraging investment returns.
The U.S. Small Cap Value Portfolio may lend its portfolio securities to generate additional income.----------------------------------