The FHFA (Federal Housing Finance Agency) released their House Price Index, which measures home price appreciation on single-family homes with conforming loan amounts. Different than Case Shiller, it does not include cash buyers or jumbo loans. The FHFA reported that prices were down 0.7% in December and only 0.1% after seasonal adjustments. Year over year, home prices are still up 6.6%. From the peak, home prices according to FHFA are down 2.7% raw, and only 1% after seasonal adjustments. Based on this, you can interpolate that the decline in Case Shiller is coming from higher priced homes where there is less demand. Additionally, there is likely cash discounts being offered, where buyers paying in cash are able to command a lower price, which is why Case Shiller is also lower.