Not sure if this is nationwide
I walked past Quicksilver on Pitt Street (it's actually on King next to the HSBC) and there were signs saying 60% off everything. Most likely clearing out stock but they still had plenty of good bargains for Christmas presents.
I bought a pair of men's board shorts that were $79.99 and after discount marked down to $31.99.
Not sure how long the sale is on for
They also had wet suits and accessories included with the sale.
They have been on sale for the last year or more. Check google maps, they were previously up to 70 off lol