Biggerboat, short sellers borrow shares from existing holders....

Biggerboat, short sellers borrow shares from existing holders. The large short sellers (NAB/MLC and UBS seem to stand out on the ASX) borrow from super funds as well as their own clients (often their own clients under other subsidiaries/regions). The main "advantage" given for short selling (and curiously HFT) is increased liquidity. This does occur, as it does through money laundering and tax avoidance practices -- in other words, the medicine is worse than the problem.

Gillysrooms, that ad for Sweden is highly distorted. Yes, basic corp tax is 22%, but company social security tax is 31% of payroll. Personal tax kicks in at 31% above about AUD $3.5K, 51% above about AUD $85k, and 56% above about AUD $110k. And while we complain about raising GST to 15%, in Sweden it's already 25%. You might also want to read Sweden's current woes on immigration policy costs. They're in a real fuddle. The grass isn't always greener in someone else's backyard (as someone who has lived half a life elsewhere and regularly travels Europe and North America).

Also, your comment about ex-div effect is correct...and incorrect. Theoretically, ex-div dates cut the share price by ex-div and franking value, but sometimes much more and sometimes not at all. Depends on market trend and share's fundamental value at the time. Not as obvious or predictable as you imply.