It's the latest twist to the Minneapolis company's struggles to stay relevant as more and more people buy electronics online. Over the past year it has announced a major restructuring plan and fired its CEO. The company is attempting to revamp itself to avoid the fate of its rival Circuit City, which went bankrupt in 2009, partly because of changing shopper habits.
The offer, made by co-founder and former Chairman Richard Schulze, values the company at as much as $8.84 billion. Schulze already has a 20.1 percent of the stock in the company, so paying for the rest of shares would mean coming up with about $6.9 billion.
Shares of Best Buy rose 15 percent in morning trading.
Schulze had served as the Minneapolis-based company's chairman until resigning in May after the scandal involving CEO Brian Dunn, who left amid allegations that he violated company policy by having an inappropriate relationship with a female employee. An investigation related to the matter said Schulze knew about the relationship and failed to alert the board or human resources.
Schulze had been expected to stay on the board until the company's annual shareholder meeting in June, but he resigned unexpectedly before the meeting and said he was exploring options for his hefty stake in the company. Analysts had been expecting a possible bid since that announcement.
"There is no question that now is the moment of truth for Best Buy and that immediate and substantial changes are needed for the company to return to its market-leading ways," Schulze said in a statement. "After assessing all of my options, it is my strong belief that Best Buy's best chance for renewed success is to implement with urgency the necessary changes as a private company."
Schulz said he wants to pay between $24 and $26 per share for Best Buy, which represents a 36 percent to 47 percent premium over the company's Friday closing stock price.
Based on Best Buy's 339.9 million outstanding shares, the offer values the company at $8.16 billion to $8.84 billion.
Best Buy said the offer came to it in a public letter addressed to the board and that it is "unsolicited (and) highly conditional," but said it would consider the offer.
Schulze said he would have preferred to pursue a deal privately but went public with the offer for the sake of speed.
"I am deeply concerned that further delay and indecision will cause additional loss of both value and talented leaders who are now uncertain of the company's future," Schulze said in a statement.
In his letter to Best Buy's board, Schulze said he has a plan to deal with the company's challenges and has talked with private equity firms about joining in a deal. Schulze said he would finance the deal through a combination of private equity investments, about $1 billion of his own equity and debt.
Analysts said it's too early to say if the offer would succeed. Several thought it was more of an opening of discussions than a final bid.
Morningstar analyst R.J. Hottovy said an offer of $30 per share might be a better price.
"It may take a larger deal to get all shareholders on board for this," he said.
Best Buy has been shrinking store size and focusing on its more-profitable products such as mobile phones. It's also trying to combat the so-called "showrooming" of its stores - when people browse at Best Buy but purchase electronics goods elsewhere, especially online.
In March, it announced a major restructuring that includes closing 50 stores, cutting 400 corporate jobs and trimming $800 million in costs.
But since Dunn's departure, interim CEO Mike Mikan has made strong statements about how he plans to restructuring the company, focusing on services and revamping stores.
In early July, Best Buy said it would lay off 600 staffers in its Geek Squad technical support division and 1,800 other store workers.
Shares rose $2.72, or 15.4 percent, to $20.36 in morning trading. The stock has fallen about a quarter since the beginning of the year.