100S Schedule B: S Corporation Depreciation and Amortization (2025)

Who files this form

Schedule B (100S) is for S corporations only. Use it to calculate depreciation and amortization for California tax purposes, and attach it to Form 100S.

An S corporation does not need to complete Schedule B for pass-through entities except to include an IRC Section 179 expense.

If the S corporation directly owns a passive activity, complete a separate Schedule B and write “Passive Activity” at the top.

What you'll need

Have these forms and records available:

• Federal Form 4562: Schedule B uses federal depreciation from line 22 and federal amortization from line 44.
• Property records: You need each property's description, acquisition date, cost or other basis, and depreciation or amortization allowed or allowable in earlier years.
• California calculation details: For depreciation, provide the method, life or rate, and current-year amount. For amortization, provide the Code section, period or percentage, and current-year amount.
• Corporation information: Enter the corporation name and California corporation number.
• If claiming Section 179: Gather qualifying property costs, elected costs, any disallowed deduction carried over from 2024, and business income information to complete the Tangible Property Expense Worksheet.
• For a directly owned passive activity: Use form FTB 3801 and its California Passive Activity Worksheet.

How to file

Attach Schedule B (100S) to Form 100S. Use additional sheets for depreciation or amortization if necessary.

• Part I: Enter federal depreciation and calculate California depreciation. Transfer the difference on line 4 to the applicable line of Form 100S, Side 6, Schedule K. Enter the Section 179 deduction on Part I, line 5, and Form 100S, Side 2, line 12.
• Part II: Enter federal amortization and calculate California amortization. Transfer the adjustment on line 4 to the applicable line of Form 100S, Side 6, Schedule K.
• Part III: Combine Part I, line 4, and Part II, line 4. Enter the result on Form 100S, Side 1, line 5, subject to the separate rules for passive activities.

For a directly owned passive activity, complete a separate Schedule B labeled “Passive Activity.” Enter the current-year depreciation adjustment in Part III and on FTB 3801, Side 2, California Passive Activity Worksheet, column (e). Label column (c) “Schedule B (100S).” Do not put that passive-activity depreciation adjustment on Form 100S, Side 1, line 5.

Common mistakes

• Including Section 179 expense in Part I, line 1. The form says to leave it out of that line and report it separately on line 5.
• Entering more than $25,000 on Part I, line 5. The form expressly limits this entry to $25,000.
• Applying the Section 179 limit separately to each asset. Include all qualifying assets because the limit applies to them as a group.
• Failing to reduce California depreciable basis after electing Section 179. Reduce the basis by the Section 179 expense.
• Claiming Section 179 for listed property used 50% or less in business. That property does not qualify for the deduction.
• Leaving negative adjustments unmarked. Use brackets for negative amounts on Part I, line 4; Part II, line 4; and Part III, line 1.

Questions people ask

Can I simply use my federal depreciation amount for California?

Not necessarily. California and federal law have differences that affect depreciation and amortization. Schedule B compares the federal amounts with the amounts calculated for California.

What is the California Section 179 deduction limit for 2025?

The maximum is $25,000. That amount is reduced if the total cost of Section 179 property placed in service during the taxable year exceeds $200,000. The deduction also cannot exceed the S corporation's business income. Use the Tangible Property Expense Worksheet to calculate it.

Can an S corporation use MACRS depreciation?

Yes, S corporations are allowed to use the Modified Accelerated Cost Recovery System (MACRS). However, California does not allow MACRS for assets placed in service while the S corporation was taxed as a C corporation. The text identifies this as a change of accounting method requiring Franchise Tax Board consent.

How are Section 197 intangible assets amortized?

California conforms to IRC Section 197. Generally, qualifying intangible assets are amortized using the straight-line method over 15 years. Federal and California amounts may differ for intangible assets acquired in taxable years beginning before January 1, 1994.

Official sources

• https://www.ftb.ca.gov/forms/2025/2025-100s-b.pdf