Subject: Re: OT: S&P 500
Is this heavily skewed by the big 7? how does say RSP compare against historical norms although i suppose it to has benefited from lower interest rates, taxes and greater share of gdp

It's a fair bit of work to provide exactly equivalent results with historical context. (I could, but I'm lazy)
So I don't have an immediate answer for comparing today to the past.

However, we can look just at today.

Though it's not as bad as during the tech bubble, the very largest firms are once again quite richly valued based on current earnings.
(which may or may not be a problem, depending entirely on what the future earnings come out like--separate discussion)

The big tech 7 of the S&P 500 (excluding Berkshire) have a simple average earnings yield of 2.50%, equating to a P/E of 40. That's AAPL, MSFT, GOOG+GOOGL, AMZN, NVDA, TSLA, META.
(Those 7 on a cap-weight basis have a weighted average earnings yield of 2.84%, equating to a P/E of 35.2, but if you're interested in RSP/equal weight, it's the simple average that matters)

For comparison, the rest of the index have a simple average earnings yield of 5.53%, equating to a P/E of 18.1
So, before taking into account future prospects (which is of paramount importance), the big 7 tech do seem to be very richly valued compared to the rest of the crowd: over twice the price for each dollar of current earnings.

None of these earnings figures I used is cyclically adjusted.
But we're not smack in the middle of a bear market, and we're doing an apples-and-Apples comparison (sorry), so it's probably not a gigantic problem.

Jim