There is mechanics in place to influence on the market forces.
But since we have a debt ratio over 10%, the system is protecting STEEM price, avoiding the increase of it's inflation.
I detailed how exactly it works a bit more here: https://esteem.app/sbdpotato/@phgnomo/how-sbd-peg-actually-works-or-how-the-sbdpotato-conversions-won-t-affect-sbd-price