Walmart, arguably, stands to gain more than any other company by this change, at least in relative terms.

Walmart has a LOT of their support workforce employed outside of Canada.  While the people working in their retail stores obviously need to be local the bulk of their distribution network is in the U.S. or overseas and most of their backend staff is in the U.S.  So proportionately they probably have fewer employees who will be impacted by this change than Loblaws or Metro who, in turn, probably have proportionately fewer employees impacted by this than any smaller or independent grocers.

Additional Walmart has virtually unlimited capital, so they can weather any transition period better than even the biggest Canadian retailers.  The small and independent retailers don't have anywhere near the access to capital so are much more strongly impacted over the short-term.

Walmart is probably pretty happy with this change.