Struggling men's retailer Jos. A. Bank Clothiers Inc. is bidding to secure its future with the $2.3 billion offer it made for larger rival Men's Wearhouse.

Men's Wearhouse spurned the offer, made public Wednesday by Jos. Bank, saying it significantly undervalues the retailer and its potential for growth. But Jos. Bank said late in the day it was undeterred.

Hampstead-based Jos. Bank, known for its deep discounts, is struggling to attract shoppers as it shifts away from such promotional deals on suits and shirts. Its sales and profits have slumped and its stock has languished even as sales of men's tailored apparel have rebounded. In June, it said it would pursue growth through acquisitions.

Men's Wearhouse, meanwhile, has seen sales grow in its stores and recently acquired menswear brand Joseph Abboud.

Jos. Bank said it made an informal offer to buy Men's Wearhouse in mid-September, tentatively bidding $48 a share cash for the Houston-based retailer. Such a deal would combine Jos. Bank's 602 stores with the 1,143-store Men's Wearhouse's chain, creating a men's tailored apparel giant with $3.5 billion in sales that could better compete with department stores.

By making its bid public, Jos. Bank appears to be appealing directly to Men's Wearhouse's shareholders in an effort to garner their support for the deal, said Karyl Leggio, dean of the Joseph A. Sellinger School of Business and Management at Loyola University in Baltimore.

Wednesday's back-and-forth between the two suit sellers could just be the start of negotiations, she said, suggesting Jos. Bank may have been bargain hunting with its first offer.

"This isn't unusual," Leggio said. "There's a lot that could happen. This is the first shot over the bow. There will be more I would expect."

One observer doubts a merger will happen.

"In the end, I don't think it will work out — the deal looks fairly crazy to me," said Howard Davidowitz, chairman of Davidowitz & Associates, a New York-based national retail consulting and investment banking firm. "Here you have Jos. Bank, a company in collapse. They've run their own business into a terrible situation."

In an interview Wednesday, Jos. Bank CEO R. Neal Black said the retailer plans to continue to pursue a "friendly" acquisition. Men's Wearhouse stock jumped nearly 28 percent Wednesday, closing at $45.03 per share, while Bank's stock was up 6.4 percent, closing at $44.33 per share.

Jos. Bank's offer represents a 39 percent premium to Men's Wearhouse's 30-day average closing price of $34.51 per share.

"Given the premium to the stock price at Men's Wearhouse, we still believe it is very compelling to the Men's Wearhouse shareholders," Black said. "We're hoping they'll reach out to management and the board to tell them to explore with us the merits of the acquisition. We're eager to enter into discussions with Men's Wearhouse as quickly as possible and pursue a transaction on a friendly basis."

He added that Jos. Bank has no plans to pursue a hostile takeover.

But the premium offered by Jos. Bank's cash offer didn't entice the leadership of Men's Wearhouse.

"The board and management team are confident that continuing our strategic plan will create more value for shareholders than Jos. A. Bank's inadequate, highly conditional proposal," said Doug Ewert, Men's Wearhouse CEO and president, in a statement Wednesday morning.

Later in the day, Men's Wearhouse adopted what is known as a "poison pill" to make an unfriendly acquisition of the retailer more difficult. It established a termporary shareholder rights plan that would allow existing shareholders to buy more shares at a discount if one shareholder buys 10 percent or more of the company's stock.

In a statement late Wednesday, Jos. Bank called Men's Wearhouse's response "inexplicable."

"Our price is significantly greater than the highest price at which Men's Wearhouse's stock has traded over the last five years," the statement said. "The formulaic, knee-jerk rejection by Men's Wearhouse, and their refusal to even discuss our proposal, do not serve the interests of their shareholders or their customers."

But at least one analyst suggested the bid should be higher.