Spread
The spread is the difference between the price at which a security can be bought (ask) and the price at which it can be sold (bid) at the same moment.
It's a hidden cost of every trade: if you buy and sell straight away, you lose the spread. On heavily traded stocks it's minimal, on illiquid ones it can be wide. In the news "spread" also refers to the yield difference between two countries' government bonds, such as Italian BTPs and German Bunds.
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