Key takeaways
- The New Jersey S corporation return is the CBT-100S, not a CBT-1065.
- The federal Form 1120-S for calendar 2026 is due March 15, 2027, and the New Jersey date is later, so calendar them separately.
- The New Jersey minimum tax for an S corporation runs from $375 to $1,500, set by New Jersey gross receipts.
- File Form CBT-200T by the original due date and include the tentative tax payment.
- The New Jersey S election is a separate Division form, CBT-2553, so check it for every client that became an S corporation.
The return is the CBT-100S, not a CBT-1065
A New Jersey S corporation files Form CBT-100S, the S Corporation Business Tax Return. The Division's corporation returns list also includes the CBT-100 for C corporations and the CBT-100U for unitary combined filers. It does not list a CBT-1065, so do not put a partnership form name on an S corporation file.
The federal Form 1120-S is the document you will request most often, but the CBT-100S needs New Jersey figures that the 1120-S does not show, including the split of receipts by destination. Keep a separate state workpaper for each client, and do not copy the federal return into the state return.
Due dates for tax year 2026
The federal rule is the 15th day of the 3rd month after the end of the tax year. For a calendar 2026 S corporation, Form 1120-S is due March 15, 2027, which is a Monday. The IRS instructions show how the weekend rule works: the 2025 return was due March 16, 2026, because March 15, 2026 fell on a Sunday.
New Jersey uses a different calendar. The Division's filing page states that the due date for the filing of a CBT-100 is the 15th day of the fourth month following the ending month of the accounting period. For a calendar year, that gives April 15, 2027 for tax year 2026.
Confirm the CBT-100S date in the 2026 CBT-100S instructions before it goes on the client calendar. The CBT-100 rule is the general corporate rule, and the S return instructions are the document that sets the S date for the year you file.
Calendar the federal and state dates as two separate deadlines. A client with a fiscal year-end counts from its own year-end, because both rules run from the end of the tax year, not from the calendar.
Extension: file CBT-200T by the original due date
New Jersey's extension is Form CBT-200T, the Tentative Return and Application for Extension. The Division states that it grants an automatic six-month extension of time to file the CBT-100, but only when the CBT-200T is postmarked on or before the original due date. Six months from April 15, 2027 runs to October 15, 2027.
The CBT-200T must include the tentative tax payment. A request without the payment is not a complete extension request, so the client sends the estimate in April with the form.
Decision rule: if the client cannot estimate the New Jersey tax by April, estimate from the 2025 return and the minimum tax tier, pay that estimate with the CBT-200T, and true up on the return. Put the estimate and its source in the file so the difference can be explained.
Failure mode: the extension goes out by mail after the original due date. New Jersey requires electronic filing for the CBT-100S, so file through the state system and keep the confirmation with the extension record.
Minimum tax: the tier is set by New Jersey gross receipts
The S corporation minimum tax is set by New Jersey gross receipts, not total receipts. The Division's table gives $375 for less than $100,000 of New Jersey gross receipts, $562.50 for $100,000 or more but less than $250,000, $750 for $250,000 or more but less than $500,000, $1,125 for $500,000 or more but less than $1,000,000, and $1,500 for $1,000,000 or more.
A C corporation starts at $500 for less than $100,000 of gross receipts. The Division says the minimum tax for New Jersey S corporations is reduced by 25%, and the $375 figure is 75% of $500.
Worked example: a client with $1,000,000 of total receipts and $250,000 of New Jersey receipts falls in the $250,000 or more but less than $500,000 tier and owes $750. Using the $1,000,000 total would put the client in the $1,500 tier, which overstates the tax by $750.
An affiliated or controlled group with total payroll of $5,000,000 or more pays a $2,000 minimum under the same Division table. Test the group before you apply the S corporation tiers to a multi-entity client.
New Jersey S status: Form CBT-2553
New Jersey S status is an election made on its own form. The Division lists Form CBT-2553, the New Jersey S Corporation or New Jersey QSSS Election, and a separate CBT-2553-R, the Retroactive S Election Application, for an election that needs to be made after the fact.
The federal Form 2553 must be filed no more than 2 months and 15 days after the beginning of the tax year the election takes effect. For a calendar 2026 election, that window closes in March 2026. Each shareholder consents by signing and dating in column K of Form 2553 or on a separate consent statement.
Shareholder consent depends on timing. If the election is filed after its effective date, every shareholder or former shareholder who owned stock between the effective date and the filing date must consent.
A late federal election generally takes effect for the following tax year, unless the corporation shows reasonable cause and acted diligently to fix the problem. Get the reasonable cause facts in writing before you tell the client which year the S status starts.
Decision rule: if a client says it is an S corporation but the file has no CBT-2553 and no CBT-2553-R, get the federal acceptance letter and the client's New Jersey filing record before you choose a return form. Bring the partner in before the 2026 return is prepared, because the state treatment decides which form is filed.
Documents to request from the client
Ask in January for the 2026 Form 1120-S workpapers or trial balance, and the Schedule K-1 (Form 1120-S) detail for each shareholder, including name, taxpayer ID and ownership percentage. Use this wording in the request: "Please send your 2026 sales by destination state, with New Jersey shipments and services tagged separately." The client can answer that from its invoicing system.
Request the New Jersey receipts split. The CBT-100S apportionment is built on receipts sourced to New Jersey, so ask for the invoice register or sales ledger with a state or ship-to field. Services need the sourcing rule in the 2026 CBT-100S instructions, so do not guess the state from the invoice address.
Request the filing evidence: the federal Form 1120-S filed copy or the Form 7004 extension status, the New Jersey CBT-2553 acknowledgment or filed copy, the prior-year CBT-100S, and proof of the 2025 minimum tax payment.
Decision rule: if the client supplies total receipts only, do not pick the minimum tax tier. Send the request in writing and hold the return until the New Jersey split arrives. The gap between the $375 tier and the $1,500 tier is $1,125 a year, and a wrong tier produces a notice.
Failure modes and fixes
Using the federal March date for New Jersey. Fix: calendar the federal March 15 date and the New Jersey April 15 date as two separate deadlines, with the October 15 extended date on the same list for calendar-year clients who file the CBT-200T.
Filing the CBT-200T without the tentative payment. Fix: pay the estimate with the form and keep the confirmation with the extension record.
Setting the minimum tax from total receipts. Fix: use the New Jersey gross receipts on the tier table, and note the source of the number in the workpaper.