Once upon a time, C# developers in investment banks were it. Banks used windows-based systems for their user-interfaces and they used window-based systems for their servers. If you could code fluently in C# within the .NET framework, you could work in either the front end or the back end. Nowadays, C# is very slowly being displaced in both.
Mike Baxter, a consultant at London-based tech recruitment firm Caspian One specializes in recruiting C# developers for investment banks. "Three years ago, you had very high paying contracts for C# developers writing interactive user interfaces for banks' risk systems. Now that UI layer is increasingly being written in web technologies," he says.
The laggards are the European banks. Credit Suisse, Barclays, SocGen and BNP Paribas are understood to remain wedded to C#.NET for both their front and back end applications. "European banks can't afford to move away from their .NET systems," says technology director at a Swiss firm. "They might want to, but you have huge existing systems and moving is just too expensive."
For this reason, Baxter says you'll always be able to find a C#.NET job with a bank, and that this job will usually pay well. In London, £550 to £750 a day is common for contract C# programmers working on "business critical systems" or developing user interfaces. Global macro hedge funds are also a repository of C# jobs: tech systems are less important in global macro and most funds have been slow to switch their systems across to angular technologies.