"a portion of costs" is correct and usable in written English.
You can use it when you need to refer to a specified quantity or percentage of costs. For example, "The company has allocated a portion of costs to the research department."
"The big issue is, are donors aware that part of the money they thought was a contribution isn't necessarily supporting the charitable mission?" Executives at several of the city's big charities said they thought most of their patrons understood the practice of covering a portion of costs with contributions.
That bonus money is nearly impossible to discern, however, because the wrestlers' share of revenue is allocated as a portion of costs of sales in WWE's financial filings.
The S.E.C. investigation concerns whether the company in 1998 improperly began to book a portion of cost overruns on construction contracts as revenue, before customers had agreed to pay any additional amounts.
The state would then pay out investor returns with a portion of cost savings, projected at $35 million.
Higher than expected enrollment means that when state taxpayers begin picking up a portion of the costs next fiscal year, they'll be facing costs far higher than promised.
If a portion of these costs were attributed to diabetes, the national cost of diabetes would be billions of dollars higher than our estimate suggests.
The Corporate segment comprises of costs incurred by the headquarters, and net of the allocation of a portion of these costs to each of the businesses.
But so far, Asian exporters have passed along only a portion of their costs.
The governor wants parents and their insurers to pay a portion of the costs.
all or a portion of the costs to the Federal Government of servicing the Federal credit instruments.
The purpose of this policy is to recover a portion of these costs.
