The Portland region posted the nation's largest annual gains in home values for the third straight month in December and the second consecutive month outright, according to the Standard & Poor's/Case-Shiller home price index, released Tuesday.

Portland-area home prices in December increased 11.4 percent year-over-year, more than San Francisco's 10.3 percent gains and Denver's increase of 10.2 percent. The trio of cities have sat atop the 20-city index for months; Portland jumped into a three-way tie for annual gains in October and claimed the highest year-over-year increases when November's numbers were released.

The monthly report is the latest in a steady stream of reminders that Portland's housing market was red-hot in 2015, a year marked by rising prices and low inventory.

"Higher prices in these markets [Portland, San Francisco and Denver] should help increase inventory headed into 2016, but at the same time push some homes out of reach for buyers," said Ralph McLaughlin, chief economist at Trulia, in an email.

Next in line on the index were Seattle - whose home values saw a 9.9 percent annual increase in December - and Dallas, where homes posted 9.6 percent gains the same month.

Between November and December, Portland home values increased by 0.4 percent. Only Tampa (0.9 percent), Miami (0.8 percent), San Diego (0.7 percent) and Phoenix (0.5 percent) posted higher monthly gains. During the same period, home prices in Denver were flat, and houses in San Francisco lost 0.2 percent of value, the index found.

Nationally, home prices increased 5.4 percent year-over-year in December, up from 5.2 percent annual gains in November. The national index increased by 0.1 percent between November and December.

"While home prices continue to rise, the pace is slowing a bit," said David M. Blitzer, chairman of the index committee, in a news release.

-- Luke Hammill

lhammill@oregonian.com

503-294-4029

@lucashammill