Execution risk

In economics and finance, arbitrage (US: /ˈɑːrbɪtrɑːʒ/, UK: /ˈɑːbɪtrɪdʒ/, UK: /ˌɑːbɪˈtrɑːʒ/) is the practice of taking advantage of a price difference between two or more markets: striking a combination of matching deals that capitalize upon the imbalance, the profit being the difference between the market prices. When used by academics, an arbitrage is a (imagined, hypothetical, thought experiment) transaction that involves no negative cash flow at any probabilistic or temporal state and a positive cash flow in at least one state; in simple terms, it is the possibility of a risk-free profit after transaction costs. For example, an arbitrage is present when there is the opportunity to instantaneously buy something for a low price and sell it for a higher price.

...
Wikipedia