Quoting the document you linked: "Constituent selection is at the discretion of the Index Committee and is based on the eligibility criteria".

The methodology is published, but largely defines eligibility; it isn't completely systematic. Even if it was, it'd still be liable to change (eg. changes to exclude some classes of shares from the float).

The indices S&P provides are used for a number of things, not all of which are retail ETFs tracking them. If you think benchmarks are never manipulated by some of the larger stakeholders, see what happened to Libor.

Libor is a wholly different type of benchmark, how is it relevant here? Even the way it was manipulated is inapplicable for stock market indices.

> The methodology is published, but largely defines eligibility; it isn't completely systematic. Even if it was, it'd still be liable to change (eg. changes to exclude some classes of shares from the float).

I do not understand the point you are trying to make here.

My point is that the publisher of the index does have more discretion than you claim they do, they are not entirely passive and rules-driven. Even where they are, they do change the rules from time to time.

They are also trying to please a number of people who depend on the index, not all of which are retail investors buying ETFs.

But passive doesn't mean that the rules never change, it's passive as opposed to active, not passive in the sense of static. There might be some kind of miscommunication here or something.