My theory is (as in my comment above) that SBDs were pegged to the US-$ at a parity and then a Korean exchange broke that in November followed by a price surge (as you would expect since the entire crypto market went up) and then in December they increased the inflation of SBDs to keep the price from going up more.
On the aspect of SP locked up in the system, I believe this is the reason why SBD is more worth than Steem. The more Steem is out of the closed system of Steemit, the narrower the gap will be.
Overall a very interesting comment of you. I will follow you now.
Thank you. Yes, I've tried to logic my way through how SBD, Steem, and SP interact and affect each other and I haven't really been able to figure it out yet. I would think the gap would narrow as people "convert" SBD to steem and SP but.....by converting it, they lower the supply of SBD so then, by definition, the SBD still out there becomes worth more. It's kind of a chicken & egg scenario. It will be interesting to see what happens as Steem becomes more and more in play to the overall crypto community....