- A cleanup of administrative processes such as HR. Standardisation of leave, expenses, release of a overly-detailed employee handbook, change of employment contracts. Exec HR contingency plans, documented reporting lines. Beyond HR, compliance may also be given more attention than usual.
- Removal of minor shareholders, cleaning up equity structure, if it was not done exceptionally well from the beginning.
- A PR push with a common focussed narrative on the companies aims & growth. Following this, announcements of comparatively minor things that support it. Lots of quotes from key management. However, as you draw closer to d-day there will be a quiet period where no information will be released as part of the process.
- Some key execs removing themselves from day to day ops while its ongoing. Guarded language during announcements as mentioned previously, especially in the final stages.
There are presumably more indicators based on the companies performance, investors and the market in general, but I think it would be guesswork without being in the loop on their corporate strategy.