Key takeaways
- Every S corporation doing business in Rhode Island files Form RI-1120S and pays at least $400, even with a loss.
- For a calendar-year entity the tax year 2026 return is due March 15, 2027, and Form BUS-EXT gives six months only if it carries a real tax estimate.
- Each nonresident shareholder is handled one of three ways: withholding on RI Schedule PTW, a composite return, or the entity-level election on RI Schedule PTE.
- I read the tax year 2025 Rhode Island instructions because the 2026 forms were not posted, so rates and addbacks below should be rechecked against the 2026 instructions.
What the entity files and pays
A corporation with a federal S election files Form RI-1120S with the Rhode Island Division of Taxation and pays the minimum tax, which is $400 for tax year 2026 and has been $400 since 2017. An LLC that elected S status federally follows the same rule. An LLC taxed as a C corporation files Form RI-1120C instead, due April 15 for calendar-year filers.
The $400 is owed whether the entity made money or not. A dormant S corporation that has not been dissolved still owes the return and the minimum.
Corporate tax at 7 percent applies only if the S corporation is taxable for federal purposes, for example under the built-in gains rules. The return then carries RI Schedule S. Ask the client whether the entity converted from a C corporation in the last five years before assuming the minimum is the whole bill.
The return starts from federal taxable income on Schedule K, line 18 of Form 1120-S, applies Rhode Island additions and deductions, and apportions the result on Schedule I using property, receipts and wages. Complete all three factors even when the entity is 100 percent Rhode Island.
Due dates and extensions for the 2026 return
Form RI-1120S is due on the fifteenth day of the third month after year end. For a calendar-year entity that is March 15, 2027, a Monday. A date that lands on a weekend or Rhode Island holiday moves to the next business day, which is why the tax year 2025 return was due March 16, 2026. A June 30 fiscal-year entity files by September 15.
The extension is Form BUS-EXT, and Rhode Island describes it as automatic for six months. The request must reasonably estimate the full tax or the $400 minimum, whichever is greater, and an extension filed without a proper estimate is void. The federal Form 7004 does not extend the Rhode Island return, so file both.
An extension moves the filing date, not the payment date. If the balance is not sent with Form BUS-EXT, interest runs at 12 percent per year from March 15 and the late payment penalty is 0.5 percent per month up to 25 percent. The failure-to-file penalty is 5 percent per month up to 25 percent.
Federally, Form 1120-S is also due March 15, and Form 7004 gives an automatic six-month extension. The federal late-filing penalty was $255 per shareholder per month for returns due in 2026; check the 2027 amount before quoting one.
Three ways to handle a nonresident shareholder
If any shareholder is a nonresident, the entity must choose a route for that shareholder's share of Rhode Island source income. Resident shareholders are outside this analysis but still need a Rhode Island K-1.
Route one is withholding. The entity withholds on RI Schedule PTW at 5.99 percent for individual, trust, LLC, partnership and S corporation members and 7.0 percent for C corporation members, which are the tax year 2025 rates. Withholding is not required if the member's Rhode Island share is under $1,000, the member is in a composite return, or the member is covered by the PTE election. The total goes on line 7c of the return's Schedule A.
Route two is the composite. A nonresident individual whose only Rhode Island income comes from pass-through entities can elect to be included in Form RI-1040C by completing Form RI-1040C-NE. The entity files the composite and pays for the electing members, who then drop out of the withholding calculation. A shareholder with a Rhode Island rental or other income outside the entity cannot use it.
Route three is the entity-level election on RI Schedule PTE, covered next. An electing entity does not have to complete RI Schedule PTW for the members it covers.
The pass-through entity election
An S corporation may elect to pay Rhode Island tax at 5.99 percent on the share of income belonging to individual members who are making the election. The entity attaches RI Schedule PTE to Form RI-1120S and issues a RI Schedule K-1 to each member it covers. The instructions say the tax must actually be paid to produce the credit.
For tax years beginning on or after January 1, 2025, the member credit is 90 percent of the tax the entity paid. Members claim it on RI Schedule W with Form RI-1040 or Form RI-1040NR and report the tax paid as an increasing modification on Schedule M, line 2h. Do not reuse a pre-2025 workpaper.
Rhode Island's own worked example shows how the schedules fit. Apportioned income is $72,700, and nonresidents hold 87.5 percent. Withholding on RI Schedule PTW comes to $2,613, and the individuals making the PTE election hold 25 percent, so $18,175 is taxed on RI Schedule PTE for tax of $1,089. Add the $400 minimum and line 8a is $4,102.
Cash-basis entities report the payments actually made in the calendar year, so April 15, June 15, September 15 and December 15 estimates plus any extension payment count toward the member's increasing modification. Accrual entities use the tax for the year. Agree on the method with the client before the first estimate.
Estimates, e-filing and the 2025 addbacks
An S corporation expecting Rhode Island tax over $400 makes estimated payments of 25 percent each on the 15th day of the 4th, 6th, 9th and 12th months. Underpayment interest is 12 percent. Withholding paid on the entity's behalf by another pass-through counts toward the tax, but the entity must attach the RI Schedule K-1 it received or the credit on line 9b is disallowed.
Rhode Island requires electronic filing and payment from larger business registrants, meaning combined annual tax liability of $5,000 or more, or gross income over $100,000. Most operating S corporations meet the second test. Register the client on the Rhode Island Tax Portal and get the PIN well before March.
For tax year 2025, Rhode Island decoupled from several provisions of P.L. 119-21. The entity adds back extra business interest expense under Code 163(j), Section 174A research amortization, extra depreciation under Code 179(b) and the sound recording deduction under Code 181, using RI Schedule HR1 - Entity and RI Schedule 174A. Each K-1 must show the member's share. For tax year 2026, read the new instructions for whether the same addbacks apply.
What to collect from the client
Ask for the Rhode Island Secretary of State ID, the final federal Form 1120-S with every Schedule K-1, each shareholder's state of residence on December 31, 2026 with ownership percentages by day if shares moved, the Form 2553 acceptance letter if the election is new, and the prior-year RI-1120S with any Schedule PTW or PTE.
Add the items that change the Rhode Island answer: estimate and BUS-EXT confirmations, property, payroll and receipts by state for Schedule I, whether the entity was ever a C corporation, and any K-1s from other pass-throughs that withheld on its behalf.
A message that works: "For the Rhode Island S corporation return, please send each shareholder's state of residence at December 31, any shareholder who moved in 2026 with the move date, and whether anyone has other Rhode Island income, such as a rental or another business." The last clause decides who qualifies for the composite.
If the client cannot say whether a shareholder qualifies, assume withholding until that shareholder returns a completed Form RI-1040C-NE. Usual can run this as a recurring request with a residency question, a not-applicable option and reminders, so answers arrive before Schedule PTW is built.