I do not invest in things, as I believe there are always risks and ups and down and it is too unpredictable. Rich people may be okay with doing that, and then it is up to them if they want to pull out or stick around for the next high.
Around the World countries whose wealth is based upon, in part, by crude oil reserves, are seeing the value of their resource plummeting. This has a knock effect in the sense such countries slow development and growth. As an example, the UAE attracts global investors to its development projects - which are partially funded by the oil reserves - and now that crude oil is plummeting, investors are selling off stocks in both Abu Dhabi and Dubai.
As crude oil falls, it will allow businesses that rely on crude oil to expand, and/or increase their earnings. This makes it a great time to invest in companies that utilize crude oil. A smart investor could work this situation to a very profitable advantage. Investors should not be worrying about the falling price of crude, they should instead be researching what entities it will help.
Where one market falls, another one rises. With lower energy prices, the price of food will fall. The price to transport goods will fall. This is going to help so many other markets that investors do not need to worry. In the end, lower energy prices will help investors and all of us.