I'll try not to start a flame war...Job ads reflect the difference between the staff a firm has and the ones it needs.In this context it means there are far more people doing C# and Java than C++, but that it is harder to get C++ skills.Choice of language is partly a function of the cost to write a line of code divded by the time to execute it. Most code in most firms is not very performance critical and even when it is the % of the system that contributes to the response time is actually quite small. Short version of that : choose the language that gets the system working soon rather than fast. C++ is faster than most other languages for most things but at the price that it is harder to program. Low latency work is often low level, changing the operating system itself and that is almost wholly the domain of C and C++, very little operating system code is written in Java or C#,Unix and Windows are C/C++ based systems, if you want to go deep and hard the only other option is machine code.It's easier to get FPGAs working with C++ than Java or C# butconversely if the heavy lifting is being done in GPU or FPGA, it may be the case that it simply does not matter what the other code is in.Also, it is the case that Java & C# skills have a lower market value, so it is rational to avoid paying C++ rates for Java work.Jobserve is sort of truthful, the jobs are not always real but the agencies would not be paying for adverts if they didn't think they would get people they could sell.But Jobserve and any other board is the spot market, it is a decent reflection of your value today, it says nothing about next year.My view is that for HFT C++ will remain the top dog for a long time, but HFT is not the same as algorithmic trading, a lot of which requires that systems are fast enough to do the trades whilst the oportunity exists but aren't trying to win many races.Those can be written in whatever mix of Java, C#, VBA, Matlab or Mathematica works for you, maybe with a bit of C++ for the most critical part.The "most critical part" varies but my view on life is that being the guy who writes this bit of code is a better position than the one who writes more code that is less critical.That doesn't always apply of course, some of the code I've got most kudos for was little more than a front end to someone else's work.