Few local landlords quibble with that argument, but they still worry the assessor will push up one of their biggest costs, real estate taxes, and depress property values. Many say Kaegi—combined with the city and state’s fiscal woes—has already cast a pall over the market, scaring off real estate investors who would normally buy property here.

Still, property owners won’t know how their higher assessments will affect their taxes until next summer, when they receive the second installment of their real estate tax bills. An assessment increase doesn’t automatically translate into a tax hike of the same percentage. What matters for an individual property owner is how much the assessment rises relative to assessed values of other properties, not the absolute change.

Taxes also depend on the levy: how much taxing bodies—mainly municipalities and school districts—decide to collect in property taxes next year. Another key variable: the equalization factor, or a multiplier determined by the state to achieve uniform property assessment.

In northern suburban Cook County, however, the numbers clearly show that the tax burden has shifted to commercial landlords.

After being reassessed, commercial and industrial properties now represent 44 percent of the $24.6 billion in total assessed value in north suburban Cook County, up from 34 percent last year. Residential real estate accounts for 56 percent, down from 66 percent in 2018.

While that’s bad news for commercial landlords, it’s good news for north suburban homeowners. Some could receive a property tax cut next year.

That wasn’t Kaegi’s goal, says a spokesman for the assessor.

“We are not purposely 'shifting the burden' to commercial property owners,” the spokesman, Scott Smith, wrote in an email. “Our statutory duty is to assess at market value for both residential and commercial. Overall, we believe we’re doing this in a fair and transparent way and that our reporting demonstrates this.”

The rest of Cook County’s property owners will find out what that means for them over the next two years. Kaegi will assess south suburban Cook County next year and the city of Chicago—home to the county’s biggest, most valuable properties—in 2021.

The big jump in assessed values stems from a key variable used to determine how much an income-producing property is worth: the capitalization, or “cap,” rate. A cap rate is an investment yield, representing a property’s net operating income divided by its price, or value. If real estate professionals know a building’s net operating income, they can use an assumed cap rate to estimate its value. The lower the cap rate, the higher the value.

Kaegi says Berrios underassessed commercial properties in Cook County by using excessively high cap rates. In Schaumburg township, for instance, Kaegi used a 6 percent cap rate to value apartments, versus 11.5 percent for Berrios. He used a 7.5 percent rate for Schaumburg office buildings, compared with 8.5 percent for Berrios.

Kaegi contends his cap rates are more accurate, based on estimates from reputable sources like Cushman & Wakefield and CBRE. Data from Real Capital Analytics backs him up: Over the past two years, five apartment complexes have sold in Schaumburg at cap rates ranging from 5.4 percent to 6.1 percent, according to the real estate research firm.

But the assessor’s new math is still hard to swallow for landlords. Kaegi’s office recently valued the Glen View, a 298-unit apartment complex in Glenview, at $41.5 million, more than double its $16.9 million value under Berrios. The assessor valued Zurich North America’s 784,000-square-foot headquarters building in Schaumburg at $187.4 million, versus $142.9 million for Berrios.

Rising commercial and industrial assessments this year exceeded residential increases in all 13 north suburban townships this year. Evanston led the pack with a 125.4 percent increase in commercial and industrial assessed values. An apartment construction boom contributed to the big jump in the north suburb, according to the assessor’s office.