Why does it seem like brokerage firms hide their offices?

I was trying to find Schwab today during a blizzard and it was real dark out. I had to go down the highway, get off, go in the direction, get off, go back in the other direction twice because they had no signs at all on their building. You wouldn't even know it was a Schwab office until you walked right up to it and saw it written on their doors. Nowhere else is it visible from the highway. I've noticed that a lot of places do this..Merrill Lynch, does it too. Why don't they have huge signs like Bank of America or Taco Bell? What other businesses don't have signs like that? It's crazy! Even though it's crazy I still opened up a Schwab One account because it's a good deal...but it's still crazy!