Oops, it doesn't look like 'Stock Open day' is a national day..

Other days

pumpkin

Pumpkin Day
nail polish

Nail Polish Day
bow tie

Bow Tie Day
frozen yogurt

Frozen Yogurt Day
ruby

Ruby Day
one

One Day
latina equal pay

Latina Equal Pay Day
cuddle up

Cuddle Up Day
artists

Artists Day
book

Book Day