"I think you have to ask yourselves if the founders would...

"I think you have to ask yourselves if the founders would knowingly pick a bad time to sell, without a great reason."

The founders have limited windows in which to sell.

A benefit flowing from the founders’ sale of shares and perhaps a motivation for the sale is to help get PME into the XTO.
With a market cap of $6.5b, PME presently ranks at about 34 from the bottom of the XTO capitalisation list.
The lowest cap stock in the XTO (SGR) presently has a market cap of a tad over $2b.

However, in constructing the index, Standard & Poor take into account the liquidity of the stock.
They consider turnover and the proportion of tradable shares in their evaluation of whether the stock is sufficiently liquid for institutional investors.
PME is at a disadvantage in this respect because more than half of the stock is still held by the two founders and so is unavailable to provide liquidity.
Any sale of stock by the founders must be bringing PME closer to being admissible to the XTO.

In the latest re-balance of the XTO, NHF $3.4b and TNE $4.6b, were admitted to the list and ARB $2.6b and SGR $2.0b were cast out.
So PME with its cap of $6.5b, must be getting closer to the front of the queue, notwithstanding its constrained share register.

More recent research suggests that the price boost when a stock is added to an index has diminished.
Back in the 1990s inclusion in the S&P500 was supposed to good for an average abnormal return of 7.6%.https://www.nber.org/system/files/working_papers/w30748/w30748.pdf

The reduction in the immediate price effect since then might be because, with greater access to data and analysis, more investors can anticipate and front-run the index constructor’s decision to include a stock and buy the stock even before any announcement of inclusion.

All four sales of the shares by the founders look like pretty disciplined exercises.
In each case, each founder sold one million shares.
In 2018 the board announced that it had urged the founders to consider selling 3 million shares each in order to improve the liquidity of the stock.
The founders fulfilled that request with sales in Mar 2018, Sep 2019, Feb 2019.

The further sale this week looks like more of the same rather than a yacht buying exercise.
In hindsight, the founders certainly didn’t do themselves any favours by selling back in 2018 at $8.

(I missed the 2018 sale when I constructing my earlier post.
The extrapolated price in 18 months’ time is just for fun, although I would happy with $81 in Sep 2024.)

Cheers