Cardiac tamponade can occur due to: 1  Dissecting aortic aneurysm (thoracic) 2  End-stage lung cancer. 3  Heart attack (acute MI) 4  Heart surgery. 5  Pericarditis caused by bacterial or viral infections. 6  Wounds to the heart.
Bid vs. ask and why yields matter. With many investments, the concept of bid and ask applies to prices. The bid price is what a buyer is willing to pay for a security, while the ask price is what a seller is willing to accept for the same security. The difference between those two numbers is known as the bid-ask spread, and in general, the narrower that spread, the more liquid the market is.
The bid and ask spread is the difference between the the price being quoted for buyers of a security and the price being quoted sellers. A trade of 1000 shares of a stock with a bid of 19.90 and an ask of 20 will incur a typical commission fee of $14.95 at your discount broker and cost 20,014.95 to execute.