I've worked in trading in NY, London, and Singapore for nearly 20 years and have never seen anyone actually write M to mean "thousands". "Thousand" is always "

I've worked in trading in NY, London, and Singapore for nearly 20 years and have never seen anyone actually write M to mean "thousands". "Thousand" is always "k" or "K". "Million" is "M", "MM", "m", "mn", or "mln".