You have the right idea, but the wrong details. You start off with one of them: " the stock will AUTOMATICALLY open down $4 on Friday morning from Thursdays's close"
No, it's not automatic, and it won't necessarily open down by the exact amount of the dividend. The market is free to open it at any auction-established price, just like with every other trade. The reason it opens lower by about the amount of the dividend is because traders are not willing to pay the same price as the day before, when on the ex-date the stock no longer trades with the right to the dividend. It's very rare for a stock to open exactly at the previous day's close minus the amount of the dividend. It can happen, but it does so far less often than not.
"when it opens $4 lower than its previous close, it will trigger all kinds of stops and pre-established sell orders"
No, it doesn't. Here's where the automatic adjustment happens: All open orders for a stock are adjusted by the amount of the dividend before the open of trading on the ex-date. That prevents pre-existing stop orders from triggering simply because of the dividend markdown. The only open orders that are not automatically adjusted down are those placed with a Do Not Reduce restriction.
"You aren't gaining anything by trying to capture the dividend unless you expect the stock to quickly recover."
I agree with that. It's silly to buy a stock just to get a dividend.
"HERC is likely going to spin out to shaeholders at close to $8, meaning those buying HTZ today are getting it for close to free."
It won't be anywhere close to free. Are you not aware that on the spinoff ex-date the price of HTZ will be adjusted down by the price of HERC, which will be established in when-issued trading before the ex-date?
If today was the ex-date and Herc closed yesterday in when-issued trading at 8, HTZ would now be trading around two bucks. This is simple, standard procedure. Have you never seen how a spinoff works before?
...And because the price of HTZ will drop so low, the company has already announced that it will reverse split the stock to get the price back up to a less embarrassing level. Somewhere between a one for two and a one for ten ratio, to be decided closer to the spinoff date.
To the genius who gave my simple statement of facts a thumbs down: From the company's SEC filing dated December 21, 2015
"prior to the Spin-Off, Hertz Holdings intends to seek stockholder approval of a reverse stock split with a
ratio equal to an integral ratio between 1-for-2 to 1-for-10, inclusive, as determined by the board of directors. The implementation of the reverse stock split would be effective immediately following the Spin-Off."
Today is indeed the ex-date. See GLBL's press release on the dividend for confirmation that dragon.slipper is correct: March 10 is the record date, not the ex-date: "The dividend is payable on March 17, 2016 to shareholders of record as of March 10, 2016."
A record date of March 10 makes today, March 8, the ex-date.
bobdbeck is correct.
"doesnt it take three days to clear"
Yes, but the ex-date takes into account the three days necessary for a trade to settle. The ex-date is the first day that the dividend doesn't trade with the stock BECAUSE it takes three days to settle a trade before the record date.
"which of the two Ex-dates do we go by and why"
May 18, 2016. Because that's the ex-date for the shares that trade in the US (the ADS). May 19, 2016 is for the shares that trade in Amsterdam and London.
"What is ADSs? I've asked this in the past and heard different answers."
Ever take a look at the company website? "ADS stands for an American Depositary Share. ADR stands for an American Depositary Receipt. An ADR is a certificate that evidences ADSs. ADSs are listed on the NYSE under the symbols RDS.A and RDS.B. Each ADS represents two ordinary shares, two A Shares in the case of RDS.A or two B Shares in the case of RDS.B. In many cases the terms ADR and ADS are used interchangeably."