What type of transaction involves the simultaneous buying and selling of securities across different exchanges?

The transaction that involves the simultaneous buying and selling of securities across different exchanges is known as an arbitrage transaction. Arbitrage takes advantage of price discrepancies between different markets. For instance, if a security is trading at a lower price on one exchange and a higher price on another, an investor can buy the security on the lower-priced exchange and simultaneously sell it on the higher-priced exchange, securing a profit from the price difference. This type of trading is usually executed quickly to minimize the risk associated with price changes.

In contrast, private placements refer to the sale of securities to a small group of investors rather than the general public, which does not typically involve simultaneous trades across exchanges. A fund of funds is an investment strategy that involves investing in multiple other investment funds rather than directly in securities, and blended payments refer to a type of investment strategy that combines various payment structures, which again does not relate to the concept of arbitrage. The essence of arbitrage lies in its focus on exploiting concurrent market inefficiencies, making it a distinct and vital trading strategy in financial markets.