sp is sold price
lp is list price
mt is market time in days.
Note however that list price is somewhat subjective. It is not the original list price, it is what the home was listed at the time it went into escrow. Also many homes have a price range and so that lp which is list price is (i believe) the high end of the range if indeed a range was used.
At any rate it does not matter to much other then to note that the trend seems to be coming down. Unfortunately we have a way to go before we reach the lows we were seeing at the end of 2008. With that said even at the end of 2008, the lows were still not spectacular by any means.
