This is a tricky one and it probably depends on the individual employer.
I would recommend looking over lots of job adverts for accountants and tallying them up. See how many ask for a masters, how many say that it’s a bonus and how many don’t mention it at all. I think that way you’ll get a good idea of what the market looks like. Be sure to diversify your job search too. Look at jobs in different regions; big cities vs. Smaller towns. Also look at accounting firms vs. In-house accountants for companies.
You may notice a trend that will enlighten you on your search, such as companies tend to ask for a masters (just an example – I don’t know if this is true!) Then, if you want to work in a company rather than a firm one day, the investment will be worth it.