Aren't you just indirectly working at FAANG then? In most cases you end up being hired by a 'talent' agency that finds work for you at these major companies.
If I understood the top-level post correctly, no. They are very much not working for a FAANG, nor for a talent agency that works for a FAANG. They're working for a company that supplies software tools to high-frequency traders or something similar. Very, very different.
(Of course, the original question was "not FAANG or HFT", so this still may not be what they were looking for...)
(Of course, the original question was "not FAANG or HFT", so this still may not be what they were looking for...)