NEW YORK • The used handbags had sold for only US$50 (S$67) two weeks ago, but prices soared to US$300 last week.

The price spurt came after news of the unexpected death of fashion designer Kate Spade last Tuesday sent shoppers rushing to buy her brightly coloured handbags, second-hand online retailers said.

Online fashion market Tradesy saw a doubling of supply and an 800 per cent increase in purchases for Kate Spade handbags on the day of her death.

"Whenever an artist of any kind passes, it's a common thing that you see; demand for their products increases and average price also increases," said Ms Kamini Lane, chief marketing officer of the Santa Monica-based company.

"But I've never seen a jump this significant before."

The 55-year-old designer, who with her husband built a fashion empire on the popularity of affordable luxury, was found dead in her New York City apartment in an apparent suicide.

Ms Lane recalled that when high-end couture designer Azzedine Alaia, who dressed stars from Greta Garbo to Grace Jones to Lady Gaga, died last November, the platform saw a spike in the sale of Alaia items, but it was nowhere close to the story of Kate Spade.

"Kate Spade was so accessible to so many people and therefore desired by a broader base," she said, adding that after Spade's death, the platform was selling "hundreds of items a day".

The brightly coloured, clean-lined accessories and bags - from the label she started in 1993 - offered a spunky style to younger working women at a time when luxury handbags were out of reach for most consumers and the industry was dominated by European brands.

Online thrift store ThreadUP said it had sold three times as many Kate Spade items on Tuesday, the day she died, than on Monday.

Items with the Kate Spade logo, primarily bags, were most in demand, with users buying more than three times as many Kate Spade handbags on the day of her death and also the day after, the company said.

Kate and her husband Andy sold their last stake in the brand in 2006.

In 2016, they launched a new footwear and accessories brand called Frances Valentine, named after their daughter. Will her death have an impact on that business? Past evidence offers some clues.

The brands that have endured the deaths of their namesake designers typically had already moved on years earlier.

Hubert de Givenchy, whose little black dresses were closely associated with actress Audrey Hepburn, died this year, but in 1995 had stepped down from his fashion house, which was recently sold to French luxury giant LVMH.

Yves Saint Laurent, who died in 2008, had also handed over the reins of his label and sold it to another French luxury group, Kering.

But other brands whose founders died while they were still in charge have not fared so well.

L'Wren Scott's clothing line, for example, was dissolved 18 months after her 2014 death.

Coco Chanel's death in 1971 left her label in a 12-year slump until Karl Lagerfeld took over in 1983.

Since taking over Kate Spade last year, New York house of luxury brands Tapestry has tried to cut back on online flash sales and sweeping promotions that some say have tarnished the brand's cachet.

But it has been off to a rocky start. Last month, Kate Spade posted a 9 per cent drop in same-store sales, sending shares of Tapestry falling more than 12 per cent.

Branding experts said Spade's death now raises a number of questions for Frances Valentine.

The line of handbags and shoes, which is carried by Nordstrom, Neiman Marcus and DSW, has yet to find the mainstream success of her namesake brand and it remains unclear who will take over.

REUTERS, WASHINGTON POST