Many F# developers work in the financial sector (myself included). Working in the financial sector isn't some magic ticket to a higher salary though, i.e., given an engineer who makes $X in some other industry, they're not automatically going to make 2 * $X just because they switch to finance. The reason salaries are higher in finance is because it's really worth the investment for financial companies to spend extra money to hire the most highly-skilled engineers (and other staff) they can find. Some other industries (e.g., aerospace) have similar requirements, so salaries are higher than normal there as well.