partially offsetting administrative costs怎么理解？

问题如下：

The method that Tong suggests to add incremental revenue is:

选项：

program trading.

securities lending.

attribution analysis.

解释：

B is correct. Securities lending is typically used to offset the costs associated with portfolio management. By lending stocks, however, the investor is exposed to the credit quality of the stocks’ borrower (counterparty or credit risk) and to risks involved with the posted collateral (market risk).

A is incorrect because program trading is a strategy of buying or selling many stocks simultaneously. It is used primarily by institutional investors, typically for large-volume trades. Orders from the trader’s computer are entered directly into the market’s computer system and executed automatically.

C is incorrect because attribution analysis is not a method of generating incremental revenue. Attribution analysis is a method that helps the manager understand the sources of return.

老师您好！请问题干中partially offsetting administrative costs怎么理解？为什么securities lending可以做到？谢谢！