Controlling interest in the Sacramento Kings NBA franchise has been purchased by Chris Hansen’s investor group, according to multiple media outlets Sunday night citing NBA sources. The sale reportedly is for $525 million, which includes the Maloof family’s 53 percent share and the share of one minority owner.

The deal, which was disclosed to teams Sunday night, requires league approval, presumably before the NBA’s March 1 deadline to apply for relocation. If it is approved, the Kings would be moved after the season ends in April and play for at least two seasons in a modestly renovated KeyArena.

Update: In a release at 7 a.m. PT today, the NBA said it received the offer from Hansen:  “The NBA received an executed Purchase and Sale Agreement for the transfer of a controlling interest in the Sacramento Kings from the Maloof family to an investor group led by Christopher Hansen. The proposed transaction is subject to the approval of the NBA Board of Governors and has been referred to the Board’s committee process for review.”

Commissioner David Stern said last week that he will permit a a counteroffer by business people organized by Mayor Kevin Johnson to keep the team in Sacramento, a plan that must include a new arena downtown. The Seattle sale approval and the Sacramento effort could proceed simultaneously. Sources said that there has not yet been an agreement submitted on the remaining 35 percent of the franchise, which is held by minority shareholders. That would leave the actual cash amount to the Maloofs at around $340 million. The expectation is if the transaction is completed, the minority shareholders may be bought out.

The deal calls for the Maloofs to receive a non-refundable $30 million deposit from the Seattle group by Feb. 1.

Johnson said the city is in a “six-week sprint” to put together a proposal for the NBA’s Board of Governors (owners). The Maloofs, who according to ESPN.com will retain a small share of the Kings but have no operational control, a year ago backed out of agreement funded mostly by the city to keep the Kings by building a new arena downtown. In the past week potential members of the would-be group have suggested an alternate site, which would slow the approval process.

Johnson released a statement Sunday night, which read:

“Sacramento has proven that it is a strong NBA market with a fan base that year in and year out has demonstrated a commitment to the Kings by selling out 19 of 27 seasons in a top 20 market and owning two of the longest sellout streaks in NBA history.

“When it comes to keeping the team in our community, Sacramento is playing to win. In particular, we have been focused like a laser on identifying an ownership group that will both have the financial resources desired by the NBA and the vision to make the Kings the NBA equivalent of what the Green Bay Packers have been in the NFL.”

The Sacramento Bee reported that political strategist Chris Lehane, who is advising Johnson, said Saturday night the deal with the Seattle group “was fairly expected.

“I don’t think it changes anything,” Lehane said. “We have our game plan.”

Lehane said the mayor has been approached by at least three investor groups that “would qualify under the definition of a whale” and are interested in buying the team.

Final approval of Hansen’s proposed $490 million basketball/hockey arena in SoDo awaits completion of an environmental impact study that must consider at least one alternate site. The study is not expected to be complete until late in 2013. The site choice is also the object of two lawsuits that claim that a third sports venue so close to the port and downtown would have large negative impacts on business and traffic in the area.

It’s not clear how the NBA owners will view the unresolved site selection in deciding to approve the Seattle purchase bid. The Kings, seen by many as a lame-duck team, have the NBA’s lowest attendance and another year like this one in Sacramento would be grim.