Orwell offers a lot of advice on writing well, a vital skill for any investor, in his essay “Politics and the English Language”
This postpulls out some of the main “bad habits” to be avoided.
It matters because writing clearly reveals understanding.
“You can shirk it by simply throwing your mind open and letting the ready made phrases come crowding in. They will construct your sentences for you — even think your thoughts for you, to certain extent — and at need they will perform the important service of partially concealing your meaning even yourself.”
“A scrupulous writer, in every sentence that he writes, will ask himself at least four questions, thus: What am I trying to say? What words will express it? What image or idiom will make it clearer? Is this image fresh enough to have an effect? And he will probably ask himself two more: Could I put it more shortly? Have I said anything that is avoidably ugly?“