Cook County Assessor Fritz Kaegi announced in February that he would revert the values of 559 commercial properties, mostly in the city’s central business district, to the 2021 values set by his office. Almost all those building owners — 551 of them — challenged Kaegi’s reassessments at the higher figures this year, and 439 of them were granted reductions. This cut about $1 billion from the total assessed value of the properties, down to a cumulative $3.6 billion from $4.6 billion.