From my country on Alliance server:

xxxxxx Tanks on sale for $xxx each (Until -171382 seconds from now)
xxxxxx Turrets on sale for $xxx each (Until -168764 seconds from now)
xxxxxx Bushels on sale for $xx each (Until -101161 seconds from now)

then a few minutes later:

xxxxxx Tanks on sale for $xxx each (Until -171597 seconds from now)
xxxxxx Turrets on sale for $xxx each (Until -168979 seconds from now)
xxxxxx Bushels on sale for $xx each (Until -101376 seconds from now)

so yes, looks to be counting to -172,800, in seconds
- - -
Edit: Confirmed

xxxxxx Tanks on sale for $xxx each (Until -172799 seconds from now)
xxxxxx Turrets on sale for $xxx each (Until -170181 seconds from now)
xxxxxx Bushels on sale for $xx each (Until -102578 seconds from now)
then
0.3 mins ago
xxxxxx Tanks were returned from the market.

I saw the timer go to -172828 seconds on my Sell Goods page.