On Jan. 27, a frightening notice arrived on the doorsteps of 36 apartments in the heart of Portland's Jade District, a hub of the Asian community along Southeast 82nd Avenue.

The notice said utility charges were going up for all units in the building, called Douglas Square. That amounted to a 10 percent rent hike for a two-bedroom apartment, from $795 a month to $845.

For the dozens of first-generation Cantonese immigrants in the building—few of whom speak English—that represents a sizable sum.

"It's a huge amount," says one resident, who asked not to be identified for fear of reprisal from the landlord. She says her family moved to Portland from Guangzhou, China, for a better life. "Now it seems like it's not better. The price of food, the rent and tuition is increasing, and we are making the same amount."

The utility charge increases, which go into effect May 1, are a warning sign of a significant shift in the Portland housing market—and another dilemma for city leaders trying to keep housing affordable.

The previous landlord at Douglas Square, one of the city's largest, has for decades been renting out the apartments to the working class, raising rents slowly on a building that was built in 1974 and hasn't changed much since.

But the real estate magnate, Joe Weston, is now transferring his holdings to his charitable foundation, which is selling them off in order to give away the proceeds.

The new landlord at Douglas Square—a California-based company called Cascade Investments—is coming in, fixing things up and raising prices on immigrant families who fear even larger hikes are in store.

In the coming years, more apartments from Joe Weston's extensive holdings could be exposed to dramatic rent increases.

That presents a test for Portland City Hall, which has pledged to keep the city from becoming too expensive for working-class residents.

But the city's Housing Bureau had an opportunity two years ago to buy Douglas Square and keep it affordable.

It didn't.

"The city talks a better talk than they did 10, 15 years ago, but in terms of dollars spent, I just haven't seen it in the Jade District," says Duncan Hwang, associate director of the Asian Pacific American Network of Oregon. "We don't have affordable housing at all. The Douglas Square building might have been our first, but they didn't go with that."

Douglas Square was sold in November to an investor for $2.6 million. The proceeds went to the charitable Joseph E. Weston Public Foundation.

Weston is one of the largest apartment landlords in Portland. He owns an estimated 2,500 apartments, many of them older, motor-lodge-style buildings nestled in neighborhoods across Northeast and Southeast Portland.

Weston has been slowly donating his real estate holdings to charity. In the past five years, Weston has sold 750 apartments, he says, adding he's already picked the next three or four buildings to transfer to his foundation.

"I'm in the process of getting rid of them," he said, noting he's 79. "I'm not going to live forever. I'm not Methuselah."

Weston's foundation is set up as a branch of the Oregon Community Foundation, which has the general mission to "improve the lives of all Oregonians." In 2014, the latest year for which its financial records are publicly available, Weston's foundation donated $939,810 to the Archdiocese of Portland, $562,000 to Central Catholic High School, and a half-million dollars in scholarships to private-school students and college kids in their first year at an Oregon public university.

Hwang wonders why some of that money didn't go to the Cantonese immigrants affected by the sale.

"I would think foundations would have a higher duty not to do harm in real estate investments," Hwang says.

Weston says he's willing to sell his buildings to housing nonprofits—to do his part to keep the units affordable.

"I'd give preference if they could come up with the money," he says.

In 2014, the housing nonprofit Rose Community Development Corporation asked the Portland Housing Bureau for a $4.6 million loan to buy and refurbish the building. Among its reasons for asking for the funding was the "vulnerable" immigrant population served by the building.

The city chose to fund other projects instead.

"Unfortunately, there's a history of the city acting too late on gentrification," says Nick Sauvie, director of Rose CDC.

Commissioner Dan Saltzman, who oversees the Housing Bureau, says the city didn't have enough money in its 2014 budget for a loan to buy Douglas Square. "It's especially important to focus on areas that are in the beginning stages of gentrification," Saltzman says, "like East Portland."

The city now says it's ready to buy Weston's properties.

Director Kurt Creager of the Housing Bureau says the agency's proposed budget this year includes a rental rehabilitation program designed to buy market-rate but low-cost rental buildings that go up for sale.

"The Portland Housing Bureau will be prepared to facilitate acquisition and preservation of these market-affordable units when and if they are made available by the Joseph E. Weston Public Foundation," he says.