Under water means that the asset is worth less than what was paid for it.
This usually refers to a loan on an asset that is more than the asset is worth.
A homeowner is underwater if their mortgage exceeds the value of the house.
Underwater situations can often, but not always, be avoided by looking for good deals and creating a margin of safety between the value of the asset and the amount of the loan.
Preliminary analysis in financial markets refers to the forecasting of various indicators, economic and financial, by evaluating past and present data and parameters.
A good delivery is understood as an unhindered transfer of ownership of a security from the seller to the buyer in compliance with all necessary requirements.
Arbitrageurs are investors who exploit market inefficiencies of any kind. They are necessary to ensure that inefficiencies between markets are smoothed out or kept to a minimum.
A beneficial owner is a person who enjoys the benefits of ownership, despite the fact that the ownership of the property is registered in a different name.
The bid-ask spread is the difference between the highest price a buyer is willing to pay for an asset and the lowest price a seller is willing to accept.