Leasehold improvements made by either the lessor or lessee pursuant to a lease qualify for special tax treatment if placed in service (i.e., the work is completed) before the end of this year and certain other conditions are met. You can:
Talk to a tax advisor for the best way to write off your leasehold improvement costs.
Interest on debt used to carry investments, but not including interest expense from a passive activity. Deductions are limited to net investment income.