“Foreign investment continued to flow into multifamily product,” JLL notes. “Inbound capital flows contributed nearly $7.3 billion of acquisitions in 2016,” with investors from Canada and the Middle East remaining the most active.

CHICAGO—There is always a bit of suspense after a sector takes off and developers break ground on a host of new projects. That's when people start to carefully watch the flow of new tenants and gauge whether the level of demand justifies all that new construction. The multifamily market in the US has been one of those rapidly expanding sectors, and so far, the new supply seems well-matched by the desire among consumers for new homes.

As a result, overall rent growth remained strong in 2016, coming in at 3.8%, according to a fourth quarter investment outlook published by JLL. And despite the thousands of new units delivered, the national vacancy rate held steady at 4.4%, roughly the same rate seen for about five years. Furthermore, the national absorption rate of 1.6% was unchanged quarter-over-quarter, and absorption was positive in the nation's top 40 markets.

All of these positive trends had a big influence on investors. In 2016, multifamily investment sales totaled $150.3 billion, a new record and a 4.3% boost over the total for 2015.

A closer look at these numbers also shows that the apartment boom has taken hold in secondary markets. In the fourth quarter, investors spent $11.5 billion on multifamily properties in secondary markets, bringing the year-end total up to a record $82.7 billion, an increase of 8.2% over 2015.

“Foreign investment continued to flow into multifamily product,” JLL notes. “Inbound capital flows contributed nearly $7.3 billion of acquisitions in 2016,” with investors from Canada and the Middle East remaining the most active.