Institutional investors rank Boston as the second-most desirable U.S. market for investment in 2021 and the only non-Sunbelt metro in the top four.

Greater Boston’s expanding life science market played into its move up from third in the previous year’s survey, as the pandemic shifted demand away from office properties.

“All of them are investing in life science and that is a real appeal of Boston,” said Gunnar Branson, CEO of the Association of Foreign Investors of Real Estate (AFIRE), which polled members in March.

Sunbelt markets with population growth ranked high in the survey, with Austin, Texas taking the top spot and Dallas and Atlanta ranking third and fourth.

“The biggest issue is where the population is growing with educated young people attracted to tech and biotech, not dissimilar to what’s causing the growth in Boston,” Branson said.

AFIRE members cited tax policy as their biggest risk factor, with 26 percent saying they were “very concerned” about increasing tax rates. Public health concerns led the list of social and political risks.

Until 2021, no tertiary market had ever topped the survey. Over 60 percent of respondents plan to increase investment in tertiary markets over the next three to five years, with opportunities to acquire properties at lower costs and less regulatory hurdles in the Sunbelt, Branson said.