It is the other way around. When STEEM is converted to SP, the STEEM is locked into a contract for a period of time. It is a 13 week withdrawal period, but only when initiated. When STEEM is in SP, it is no longer liquid. Over the last few months, there has been more STEEM stored in SP than was created. The liquid supply is already small and is shrinking. This is one of the reasons that SBD is so important. When the supply of STEEM gets really low, then STEEM price would go really high and potentially volatile. SBD will be there as a stable currency.

STEEM could experience what is happening on HitBTC if the supply goes down extremely low. Right now the supply of SBD on HitBTC is stuck there. No SBD can go in or out. With low supply and high demand, then high stakes trading takes over and the price swings like crazy.

But not to worry, the supply of STEEM is not going to experience that for a long time.

https://steemit.com/philosophy/@metama/reprogramming-your-mind-day-13-i-have-a-dream