As near as I can tell it appears to represent the share that you are holding of the SP steam fund. If you look up your profile on you will see a panel on the RHS that shows how many Megavests (1 million) you have. I presume that times the vest price is something like the value of your investment. So its kind of like a share price in Steemit instead of the value of the currency. That's a head scratcher.

Coin Marketplace

STEEM 0.16
TRX 0.03
JST 0.026
BTC 12764.63
ETH 394.51
USDT 1.00
SBD 1.01