The commercial real estate market in Denver’s River North neighborhood is in a “feeding frenzy,” with $40 million in property changing hands in the past 90 days, some at prices almost three times the metro average, according to a Denver real estate firm.

In the past two years, sales in RiNo have topped $365 million for 130 office, industrial, retail, land and multifamily housing properties, according to Newmark Grubb Knight Frank research. By comparison, between 2009 and 2011, 50 properties sold for $43 million.

“It is a feeding frenzy,” said Russell Gruber, a director at Newmark Grubb Knight Frank who specializes in industrial real estate. “You’re looking at an area where people have had industrial businesses for a long time, and the values of their real estate in that market have grown. You’re starting to see this opportunity to relocate businesses.”

Another 20,000 square feet of RiNo industrial space, spread out over three warehouses, has changed hands in the past week. The warehouses — at 3911, 3925 and 3963 Walnut St. and sitting on 40,625 square feet of land — were sold for $3.5 million to 3925 Walnut Street LLC, an entity registered to developer Michael Mathieson, according to public records.

The sale price, which works out to $175.50 per square foot of industrial space, tops both the 2014 industrial average of $62.88 per square foot for the central submarket and the overall Denver-area average of $63.77 per square foot, according to Newmark, which handled the transaction.

That’s also higher than the $97 per square foot that Gold Star Sausage received in March for its 32,900-square-foot manufacturing facility at 2800 Walnut St. Developer 1425 Market LLC purchased that building for $3.2 million, with plans to “repurpose the asset to take advantage of market conditions,” according to Newmark.

At the time of the sale, Gold Star president Rick Rue said the company would keep its headquarters in Denver but move its food-processing operations to Nebraska “to expand and be closer to our suppliers.” Gold Star has operated in RiNo since 1936.

Murray Platt, first vice president of CBRE Industrial Services, said that in the past six months, large-scale institutional capital also has started to flow into RiNo, adding to the area’s credibility. Prior to that, most activity had been local investors and developers.

The average land sale price in RiNo is up, too, jumping more than $20 per square foot in 2014, according to CBRE Research.

“It is certainly a hot area,” Platt said.

Veteran RiNo developer Kyle Zeppelin said he agreed the neighborhood is seeing a lot of activity but that putting together a project still poses challenges.

“It’s not like every lot is getting developed — it’s an incremental process — but you add it up, and we’re over $100 per square foot,” Zeppelin said.

When Zeppelin Development, owned by the father-and-son duo of Mickey and Kyle Zeppelin, purchased the site for the Taxi multiuse development along the South Platte River near Brighton Boulevard, it paid about $5 per square foot, Kyle Zeppelin said. The first building opened in 2001.

Zeppelin Development has since opened The Source culinary complex in an old foundry on Brighton Boulevard. This year, it announced plans to build a boutique hotel next door.

“There are a lot of things working in a complementary way,” Zeppelin said.

Among them are the city’s upcoming improvements to Brighton Boulevard and the construction of a pedestrian bridge between 35th and 36th streets. The East Rail Line station at 38th and Blake streets will be “game changer” for the area, Zeppelin said.

The new owner of the Walnut Street warehouses has no definite plans for the property yet, Gruber said, but the proximity to the future commuter-rail station was a major selling point.

“A mixed-use multifamily development is something that’s within his wheelhouse,” Gruber said.

Emilie Rusch: 303-954-2457, erusch@denverpost.com or twitter.com/emilierusch