UPDATE 1-Costco, Sam's Club, others halt photo sites over possible breach

(Adds closing share prices, byline)
By Solarina Ho
TORONTO, July 20 (Reuters) - Costco Wholesale Corp COST.O ,
Sam's Club WMT.N and a handful of other large retailers have
disabled their online photo printing stores in recent days, on
concerns about a possible data breach at PNI Digital Media,
which manages and/or hosts photo services sites.
Last week CVS Health Corp CVS.N disabled its CVSphoto.com
site, and the week before Walmart Canada's WMT.N
walmartphotocentre.ca took a similar action after it was
informed that customer credit card data had been potentially
compromised. ID:nL4N0ZX4MF
Other photo printing sites that might have been recently
affected included Rite Aid Corp RAD.N and British supermarket
chain Tesco's TSCO.L .
"We take the protection of information very seriously. PNI
is investigating a potential credit card data issue, and outside
security experts are assisting in the investigation," said Kirk
Saville, vice president, global communications at Staples Inc
SPLS.O , which bought Vancouver-based PNI last year.
Some websites said they had been advised by PNI of a
potential breach, while others said they acted because of recent
reports.
Costco Canada and Rite Aid noted that PNI has limited access
to customer information since it does not process credit cards,
but the photo service sites were temporarily taken down as a
precaution.
CVS and Walmart Canada asked customers to monitor their
credit card transactions closely for unauthorized charges.
Tesco's page simply said it was it was unavailable for
routine maintenance.
The retailers' main websites and other services were not
affected by the potential breach.
Costco shares rose 0.2 percent to end regular trading at
$145.04; Wal-Mart shares dipped 0.4 percent to $73.10; Rite Aid
fell 1 percent to $8.82; Tesco shares ended 0.3 percent higher
at 218.6 pence, and Staples shares eased 0.5 percent to $14.63.