It depends on how the index is constructed. A market cap index cannot be value investing. A market sector index is almost surely not value investing (unless that entire sector is undervalued).

An index constructed specifically using value measures as the criteria for inclusion can be (at least arguably so).

Click on "value indexes" here: https://www.crsp.org/indexes/ to see some underlying value indexes, and funds like this one track the Large Cap version of it: https://fundresearch.fidelity.com/mutual-funds/summary/92290... (perhaps not surprising, the fund's largest holding is Berkshire B shares)

XBRL filings have the information needed to screen with value investing criteria. GFinance's old stock screener's UI was great.

https://github.com/openlink/Virtuoso-RDFIzer-Mapper-Scripts/...

/? query XBRL https://www.google.com/search?q=query+xbrl

https://github.com/topics/xbrl

But then also a fund or an index fund or an Index ETF wouldn't be complete without ethical review for the sustainable competitive advantage given e.g. GRI+#GlobalGoal sustainability reports.

When you own enough of a company to bring in a new team.

- [ ] ENH: pandas_datareader: add XBRL support from one or more APIs

https://pandas-datareader.readthedocs.io/en/latest/remote_da...

I think the larger point is that public capital markets have become steadily more efficient. There are no "value stocks" anymore because nothing is overlooked by the market, those old opportunities have been arbitraged away. Modern computing systems have made it practical to look at every stock every day, so all stocks now trade at their "true worth" because all publicly available information gets instantly priced in.

Now pretty much the only way for investors to (legally) beat the market is to do proprietary research in ways that others can't easily copy. You need information that no one else has.

As a counter-argument, you usually need to read a lot into the reported numbers, for example read the 10K notes for multiple years in the past. That's the only way to know that the 3B in assets showing up on the balance sheet for "goodwill", to use one easy example, are not really worth 3B. There are many more-nuanced factors that work alike. The reported numbers are what the accountants think might fly under GAAP, and the accountants work for the CEO, who has a say in the accounting "intent".

To test whether markets are perfectly efficient, just look for large movements over time. If a stock goes up 20% in a year, the market might have undervalued it last year, or is overvaluing it this year. It's unlikely the it was correctly valuing it at both times. In the absence of a Covid-19 pandemic, act of god, etc. of course.

You could say that the market just takes "investor sentiment" into account, and is therefore still efficient. But value investing is a strategy that looks for misplaced investor sentiment and exploits it. If that's the way you define an efficient market, than I'd say an efficient market is no obstacle to a value investor.

> If a stock goes up 20% in a year, the market might have undervalued it last year, or is overvaluing it this year. It's unlikely the it was correctly valuing it at both times. In the absence of a Covid-19 pandemic, act of god, etc. of course.

Or the company has grown its revenue by 20% in 1 year which isn't necessarily unheard of. Or they significantly beat the expectations of analysts / their own guidance. In all of those cases the stock could have been correctly valued & still experienced growth.

Sure which is why I said "unlikely", rather than "unheard of".

A 20% rise in a stock doesn't constitute evidence of market inefficiency. In most cases that increase is due to new information becoming available.

If you say that value investing still works then where is the evidence?

>To test whether markets are perfectly efficient, just look for large movements over time. If a stock goes up 20% in a year, the market might have undervalued it last year, or is overvaluing it this year. It's unlikely the it was correctly valuing it at both times. In the absence of a Covid-19 pandemic, act of god, etc. of course.

This is technical analysis not value investing.

It's not the investment thesis, it's a thought experiment to test market efficiency. It's a test to see whether markets are always efficient, and to me demonstrates that they are not, and that value investing might be an interesting thesis to pursue still.

People have been saying for decades that value investing is not possible since the market is too efficient. My point is that it is not efficient enough to prevent value investing from being a successful strategy.

The efficient market hypothesis has been dogma for about half a century, but there's a lot of academic research showing that value and various other factors outperform anyway. There are all sorts of structural and psychological reasons they might persist; e.g. a short-term bias among fund managers, who tend to lose investors if they underperform a few quarters.

The research does say that value doesn't work quite as well as it did decades ago.

There is no reliable evidence that value investing still outperforms the market on a risk-adjusted basis. Everyone knows the trick now so the trick no longer works.

There's no reliable evidence that it doesn't, either. Value has never been something that works all the time. You have to put up with lagging performance when growth stocks are ascendent, which could be a reason that value keeps working in the long term. Time will tell whether it has its day again.

"If you're not on the inside, you're on the outside!"

This doesn't happen any more. Back then you could find companies with a cap that was LESS than the money they had in the bank. Those were no brainer deals.

This strategy was actually pioneered by buffets mentor Benjamín graham. By just blindly following a formula you would do value investing by calculating NAV vs market cap.

Buffet took it one step further. He calculates another type of value called intrinsic value and that relies on other factors rather not just the ratio of assets to cap. Part of it relies on consistency of revenue, growth and qualitative aspects of the business as well.

> This doesn't happen any more. Back then you could find companies with a cap that was LESS than the money they had in the bank. Those were no brainer deals.

For a while, Yahoo was famously worth less than its stake in Alibaba. But it was also not clear whether shareholders could get management out of the way to stop destroying value.

> This doesn't happen any more. Back then you could find companies with a cap that was LESS than the money they had in the bank. Those were no brainer deals.

Plenty of companies trade at a discount to book value. I found over a thousand with a stock screener.