Debt-mired JJB Sports put itself up for sale on Thursday and warned investors their shares may be worthless, placing the sports goods retailer at risk of becoming another big-name British retail casualty.

The company has been rocked by funding issues, falling sales and stiff competition as UK store chains battle weak consumer spending, muted wage growth and government austerity measures. .

A string of household retail names including Woolworths and MFI have gone out of business in recent years, undermined by price-cutting from supermarkets and the Internet.

Directors at JJB, a familiar sight on Britain's high streets with around 4,000 staff and 180 stores, said they did not believe the company would be able to raise new funds to stage a turnaround.

Analysts said the sale process was not a surprise given the funding shortfall issues flagged by the company in July and its failed attempts to raise fresh cash from strategic partners.

JJB said that a formal sale process would start but warned that there could be no certainty that an offer could be forthcoming.

"Given the level of current debt within the company, there can be no assurance that any proposal or offer that may be made would attribute value to the ordinary shares of the company," the company said in a statement on Thursday.

Shares in the company crashed 71 percent to 0.68 pence at 0840 GMT, giving it a market value of around 3 million pounds. It was worth 500 million pounds in August 2010.

"We suspect that JJB will now follow a similar process as Blacks Leisure i.e. a likely administration process followed by the possible sale of parts of its business," said analysts at Charles Stanley.

Blacks Leisure, which like JJB was loss-making and debt-saddled, went into administration in January before the bulk of the business was sold immediately to JJB's rival JD Sports Fashion.

When retailers are bought out of administration, the buyer usually cherry-picks certain operations, which can lead to store closures and job losses.

U.S. retailer Dick's Sporting Goods threw JJB a 20 million pounds ($31 million) lifeline in April, but took an impairment charge that effectively wrote off the investment earlier this month.

JJB, which issued a profit warning in July on the back of poor sales of Euro 2012 football shirts and reported an 8.7 percent slump in first half underlying sales, said organic sales in the six weeks to Aug. 26 slipped 3.3 percent.

"It's a business that's been shrinking for the last couple of years," Seymour Pierce analyst Kate Calvert said.

"They haven't been able to find their niche in the market place and be able to take on the likes of Sports Direct and online and supermarkets."

Larger rival Sports Direct - Britain's biggest sporting goods retailer - owned by Newcastle United football club owner Mike Ashley, has consistently undercut JJB on pricing and aggressively discounted Euro 2012 kit.

JJB Sports was founded in 1971 by ex-Blackburn Rovers footballer Dave Whelan with a single store in Wigan, where the company is still headquartered.

It floated in 1994, and four years later acquired the business of Sports Division, making it Britain's biggest sports retailer at the time.

JJB owes around 36 million pounds ($57 million) in total, around half in bank debt and the other half in convertible loan notes, giving it a debt to equity ratio of 0.51, far higher than rival JD Sports which is on 0.01.