Homes are seen for sale in the northwest area of Portland, Oregon. Reuters The S&P Case-Shiller US home-price index rose to a 10.4% annualized increase in December, up from 9.5%. The reading marks the strongest pace of price growth in seven years, according to a press release. The data suggests the US housing market ended 2020 strong amid low inventory and record-low mortgage rates. Visit the Business section of Insider for more stories. US home prices surged through the end of 2020 as record-low mortgage rates kept demand at elevated levels, and a general inventory shortage propped up prices.The S&P CoreLogic Case-Shiller US National Home Price Index posted a 10.4% annualized increase in December, according to a Tuesday press release.