Fueled by a strong and diverse economy, L.A. County’s luxury home values continue to appreciate faster than anywhere else in the state, according a survey conducted by First Republic Bank.

The study measured changes in homes valued at more than $1 million in large upscale markets, including the tony enclaves of Beverly Hills, Calabasas and Malibu, among others.

In the third quarter, luxury home values jumped 8.6 percent from the previous quarter and 17 percent from the year prior. The average luxury home which ranges in size from 3,000 to 6,000 square feet and has three to six bedrooms and bathrooms was $2.3 million, up $331,000 from a year ago.

The hike in values placed luxury home prices in L.A. County at an all-time high, according to the First Republic survey. The county’s luxury homes have posted 11 straight quarters of double-digit, year-over-year gains.

“It’s amazing what’s going on,” said Barbara Tenenbaum, an agent in Coldwell Banker’s Beverly Hills office, in the bank’s report. “The market is still quite strong. Because there is a shortage of inventory and good properties, the market keeps going.”

However, the robust increase in luxury home values could be coming to an end. Real estate agents from the Bay area to San Diego said high-priced homes are staying on the market longer and sellers are resorting to cutting prices.

“There are clear signs of a slowing trend,” said Katherine August-de Wilde, First Republic’s chief operating officer. “Luxury home values and activity are expected to moderate as the market takes a breather after a prolonged period of significant appreciation.”