Stern also said the Sacramento bid is "in the ballpark" financially with the deal from a Seattle group headed by Chris Hansen, though the Maloof family disputed that in a letter to the advisory and finance committee.
Obtained by The Associated Press, the Maloofs' letter dated April 17 said the Sacramento group originally matched the $525 million valuation for the franchise agreed to by Hansen, whose group includes Microsoft Chairman Steve Ballmer. Then last week, Hansen increased the valuation offer to $550 million.
The Maloofs said the Sacramento group has asked not to enter into a binding agreement until the Seattle deal is terminated. The Maloofs said that would be a breach of contract and cost them the "leverage to aggressively renegotiate terms in the event the existing agreement is terminated."
"Based on these factors ... we and our advisers see no reason to continue any dialogue with the Sacramento group or to give any further consideration to negotiating backup offers based on its latest non-binding proposal," the letter said.
Stern said a decision will need to be made in time so that the team's placard can say either Seattle which lost the SuperSonics to Oklahoma City in 2008 or Sacramento when it reports to New York for the May 21 draft lottery.
He said owners are "deliberating quite conservatively and deliberately" because the league has never faced anything like this battle between the two West Coast cities.
"This has been wrenching," Stern said, adding that "it's the only time in the last 37, 47 years that I haven't known the answer."
The Maloofs reached an agreement in January to sell a 65 percent controlling interest in the Kings to Hansen's group at the total franchise valuation of $525 million, topping the NBA-record $450 million that Joe Lacob and Peter Guber bought the Golden State Warriors for in 2010. That implies selling the 65 percent stake for about $357 million.
Stern has said expansion is not an option right now. The Board of Governors, consisting of all 30 NBA owners, was briefed on the matter during meetings Thursday and Friday. The committee reviewing the bids also met Wednesday.
If a vote is taken at some point in the next couple weeks, the Seattle group needs 23 of 30 owners to approve the sale of the team. A simple majority 16 votes is all that's needed to approve relocation.
"There's no attempt to get any unanimity. There's only an attempt to get answers to every possible, any possible question that various owners have, and then they'll vote however they vote, period," Stern said.
The commissioner has said previously that the sale of the Kings would not become a bidding war. And yet, a bidding war is exactly what seems to have broken out.
Hansen put down a $30 million deposit, while the Sacramento group has only offered $15 million, according to the Maloofs' letter. The Maloofs also have expressed concern to fellow NBA owners about the changes to Sacramento's group, saying the reason new investors keep surfacing is because of a "lack of funds."
Led by Mayor Kevin Johnson, Sacramento has fought back over the past three months to make the sale and relocation of the Kings a real debate. Johnson pushed a non-binding financing plan for a $447 million downtown arena through the Sacramento City Council complete with a $258 million public subsidy and lined up an ownership group to try and compete with the powerful Seattle contingent.
The potential Sacramento ownership group is led by TIBCO software chairman Vivek Ranadive, who would sell his minority share of the Warriors if successful. Others who have joined the bid include 24 Hour Fitness founder Mark Mastrov, former Facebook senior executive Chris Kelly and the Jacobs family that owns communications giant Qualcomm.
Ranadive and Mastrov were copied in the letter sent to the NBA committee.
Johnson has announced new investors to join the bid over the last few weeks but has not said publicly what each person's financial contribution would be. Billionaire investor Ron Burkle, a co-owner of the NHL's Pittsburgh Penguins and once a key cog in Sacramento's group, was forced to back out of the bid two weeks ago because of a conflict of interest created by his stake in a company that manages some NBA players' careers.
Johnson was in New York on Friday but it was unclear whether he would address owners again. The mayor said at halftime of Sacramento's season finale against the Los Angeles Clippers on Wednesday night the he was "very confident" in his city's bid.
"I think the advantage has to go to the home team," Johnson said before the Kings lost 112-108 to the Clippers during an emotional season finale. "We're an incumbent."
The Maloofs also had other concerns with Sacramento's offer.
The letter said the Sacramento group extended a date to close on the transaction from May 31 to June 30, while the Hansen-Ballmer bid is ready "immediately."
The family said the Sacramento group refused a request that Kings employees' contracts were not terminated for 18 months after closing the deal. The Maloofs said Hansen's group agreed to this suggestion "without hesitation," according to the letter.
Spokesmen for the Maloof family, Johnson and Hansen said they had no comment on the letter.