If my company matches a certain level of charitable giving, can this be included in any way in ma'aser calculations? Does it make a difference if the company matches the donations by giving directly to the charity, or if it makes a contribution to my charity account, which I then use to make donations?
Shulchan Oruch Yoreh Deah 249 (1) refers to giving ma'aser:
The amount of charity one should give is as follows: if one can but afford, let him give as much as is needed. Under ordinary circumstances, a fifth of one's property is most laudable. To give one-tenth is the average disposition. But to give less than one-tenth is niggardly. When the Rabbis said a "fifth" they meant a fifth of the property the first year only and a fifth of the profits in succeeding years.
The obligation is to deduct from one's property and then one's income. The implication is that one's property and income are therefore liable to a deduction for ma'aser. The person himself has to make that deduction.
Meir Tamari in With all your Possessions p 225 writes that tithing in Judaism is part and parcel of the tax system. Tax is considered a personal obligation.
The implication seems to be that since the person himself is liable to make the payment, he cannot rely on another person to make up the amount.
Therefore the praiseworthy matched giving of the employer does not release the employee from giving what he has to give from his income.