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.
Another clue is the Bid Size and Ask Size, sometimes referred to as the âbid-ask ratio.â In the example above, the Bid Size of the last trade is 1,207 and the Ask size is 187. (The first line in the chart is the last trade.) For that second, there are more buyers than sellers.