The SP fluctuations of some ASX equities sometimes seem to move...

The SP fluctuations of some ASX equities sometimes seem to move in tandem. This is neither surprising nor sinister - especially when certain companies engage in similar activities/services &/or share BOD members, major SH’s on their Register, work in the same geographical region, etc.
There is much that is shared by EVS (Envirosuite Ltd) and PET (PHOSLOCK Environmental Technologies) apart from the previously mentioned Chinese BOD member (ZZ). Both companies hope to establish a large ‘footprint’ in China & benefit from that country’s apparent determination (& financial commitment) to clean its environment which has suffered from years of neglect during its rapid industrial growth. It seems EVS may be primarily involved with air-related issues wheras PET with water.
The SP of PET recently experienced a rapid rise & just as a dramatic retrace - not unlike the whip-lash experienced in trading currencies (as any/all FX traders will know ... only it’s much more rapid in FX!)
Whilst it may be too early to call, it seems possible that PET has commenced its recovery after hitting today’s low of $0.815. If so, any possible downward pressure on the SP for EVS from ‘cross-linking’ with PET should gradually diminish - it is possible we are already seeing that happen.