This excerpt taken from the SYMC 10-K filed May 24, 2007.
Accounting for Excess Facilities
We have estimated expenses for excess facilities related to consolidating, moving, and relocating personnel or sites as a result of restructuring activities and business acquisitions. In determining our estimates, we obtain information from third party leasing agents to calculate anticipated third party sublease income and the vacancy
period prior to finding a sub-lessee. Market conditions may affect our ability to sublease facilities on terms consistent with our estimates. Our ability to sublease facilities on schedule or to negotiate lease terms resulting in higher or lower sublease income than estimated may affect our accrual for site closures. In addition, differences between estimated and actual related broker commissions, tenant improvements, and related exit costs may increase or decrease our accrual upon final negotiation. If we made different estimates regarding these various components of our excess facilities costs, the amount recorded for any period presented could vary materially from those actually recorded.