I was an IT manager for a major Wall Street firm for near on 20 years, not an economist or accountant, but this should help explain what I mean:
One of the "hidden costs" of doing business for us (and every firm on the street) is that when we do business with, say, the State of New York (and we all do, lot's of bond issues, union funds, pension plans, etc), we're automatically tied to a pension contribution scheme by state law. The contribution is based upon age.
The younger a worker is, naturally, the smaller the required contribution. However, when the worker reaches 40 years of age (or older), the amount explodes exponentially.
For example, if I'm 39 this year, and I work for a firm that does business with NY State, then my pension liability to the firm is equal to a small percentage of my total salary (and is limited in terms of the dollar actual dollar amount. I believe this number is 3%). However, when I turn 40 the following year, my pension liability to the firm becomes an automatic, flat-rate 10k per year, and stays at that level for the length of the term of the contract with the State.
In other words, the cost of my pension to the firm, as a result of doing business with the state, costs them 10k a year until I either quit, die or retire.
Other states have similar contract requirements.
So, if I have a 40 year old, working at 50K a year, he's actually costing me 60K a year and that's BEFORE you add in the cost of insurance, retirement plan (401k) contributions (and administration), the 12% Social Security tax contribution, and providing things like days off and paid holidays or medical leave (also mandated by government).
This, of course, does not take into account things like stock option plans, bonuses, productivity lost to sick time, travel and education benefits.
The one serious (internal) study I ever saw on this subject came to the conclusion that an employee actually costs more in terms of total benefits package than salary, assuming the employee took advantage of every benefit available to them.
Like I said, much of this has to do with the nature of the business. Financial Services is one area that could easily experience a higher cost structure to pay for their benefit programs. Federal and local government regulations will also impact this percentage. However, if you look at American business as a whole, you will find that benefit costs average about 35-40% of salary and wage expenses -- nothing near the 300% you suggested in an earlier post.
Rising healthcare costs will place upward pressure on that percentage as workers continue to receive a greater proportion of their total compensation increases in benefits rather than wages.