Business Tax Filings

You can start with accounting on its own through Portside's accounting intake form. Many clients also pair it with business tax filings, nonprofit tax filings, and/or full-service payroll for full back-office support.

Portside serves service-based businesses only. We do not serve businesses whose chief business is to sell or manufacture products.

Absolutely yes! Business or nonprofit tax filings pair with accounting and full-service payroll for full back-office support from Portside.

Your extension timeframe depends on the type of return:

Personal tax returns (IRS Form 1040): Extension must be filed before April 15th each year; extended through October 15th of that year to file (not pay)

Partnership and S-corp tax returns (IRS Forms 1065 and 1120-S): Extension must be filed by the 15th of the third month after your partnership's fiscal year end. Extensions are granted for six months from the original filing due date to file (not pay). As an example, if your partnership follows a calendar year, your extension request must be filed before March 15th each year; extension applies through September 15th of that year to file (not pay).

C-corp tax returns (IRS Form 1120): Extension must be filed by the 15th of the fourth month after your corporation's fiscal year end. Extensions are granted for six months from the original filing due date to file (not pay). As an example, if your corporation follows a calendar year, your extension request must be filed before April 15th each year; extension applies through October 15th of that year to file (not pay).

Nonprofit tax returns (IRS Form 990 series): Extension must be filed by the 15th of the fifth month after your nonprofit's fiscal year end. Extensions are granted for six months from the original filing due date to file (not pay). As an example, if your partnership follows a calendar year, your extension request must be filed before May 15th each year; extension applies through November 15th of that year to file (not pay).

Most important note: any tax owed is still due by the original due date, even if you extend your tax returns.

If you are on extension with Portside, please upload any remaining documents as soon as possible so your advisor can finish before the deadline. You can read the IRS's guidance on getting an extension or our guide to filing Form 4868.

Not at all, but rest assured a human is on the other side working on your return.  Portside's process is designed to be fully asynchronous. All communication happens through your secure portal, and you’ll receive a personalized video reviewing your return. You can also ask questions directly in the portal's chat and your advisor will respond live during local business hours.