Who's behind the full-page, $2.6K Chicago Sun-Times ad supporting Mayor Brandon Johnson?

CHICAGO (WLS) -- A newspaper ad praising and thanking Chicago Mayor Brandon Johnson for things he has done since taking office raised a few eyebrows on Monday.

The ad has been causing a bit of a stir, because the group that paid for it has a vague name and is not registered with the state as a political organization. So, who is behind it is a mystery.

Johnson talked to seniors at a bingo on Monday, sounding very much like he is in campaign mode, even though his next election is still three years away.

"We've eliminated sub-minimum wage. We have the largest paid time off," Johnson said.

Johnson's message came one day after, in Sunday's Chicago Sun-Times, someone took out a $2,600 full-page ad that touted Johnson as "the people's mayor." It also listed some of the very same accomplishments Johnson was talking about to seniors.

Johnson claimed no knowledge of the group, Southside Chicagoans, which paid for the ad.

"No more than I have any knowledge of people who don't actually - who oppose my position. The people who are excited about my leadership over these first 10 months are obviously expressing that excitement," Johnson said.

But the Better Government Association said the ad raises some questions about transparency when the members of the group behind it remain a mystery.

"Mayor Johnson may have nothing to do with this at all. But nevertheless, if somebody is out there touting the mayor, we in the public realm also have a right to know who that person is," said BGA President David Greising.

Greising also noted that the timing is strange with the mayor so early in his first term.

UIC Professor Emeritus of Political Science Dick Simpson agrees, but said there's nothing illegal about what the group did or their remaining anonymous.

"So I view this is a signal of support and desire to keep the city on a progressive trajectory, particularly in comparison to what Paul Vallas would have done if he had been elected mayor," Simpson said.

The group Southside Chicagoans is not registered with the Illinois State Board of Elections, but a spokesman said the group would not have to because the ad was not asking people to vote for or against a candidate for office.

"I'm very proud of the work that we've done thus far in the first 10 months. There is a lot of work to still be done, but our message is pretty consistent: A better, stronger, safer Chicago requires a mayor that's going to invest in people and I've done just that," Johnson said.

ABC7 asked the Sun-Times for further information about who paid for the ad, and is awaiting a response.