Just to clarify, your month salary is divided into 13 instead of 12 and you get double salary in December.
It's not a bonus.
I think you mean yearly salary ( each month : year_sal / 13 instead of year_sal / 12 ). Pay for the year is chunked into 13 pieces.
Just as equally looney toon. Ask the employer to pay you less than a month's salary for 11 months just so they can double up the last month of the year???
Chuckle. How about have to employer take that "divide yearly by 13" deduction out of payrolls check each month and direct deposit into worker's savings account. That way the worker just withdraws the money at the end of year.
While not technically a discretionary bonus, it certainly smells like one. . It is only a means of making it an oxymoronic mandatory bonus by attaching it to a nonexistant month. Might as well attach it to employee able to breathe in December ... extra month pay.
I can see most retail employers playing along with this since farce because their balance sheets are often red most of the year until customers get into the holiday spending frenzy.