An individual carrying on a business wholly or partly in New York City - a one-member LLC counts as a sole proprietor - files Form NYC-202 when total gross business income, wherever earned, is over $95,000. The return takes the business income allocated to the City, allows 20% of it (no more than $10,000) for the owner's own services, then a $5,000 exemption (prorated for part of a year), and charges 4%. A tax of $3,400 or less is wiped out by the business tax credit; $5,400 or more gets none; between, the credit is tax × ($5,400 − tax) ÷ $2,000. Due April 15.
The tax left after the credit is paid with the return. If next year's tax can reasonably be expected to exceed $3,400, a Declaration of Estimated Unincorporated Business Tax (NYC-5UBTI) is due on the 15th day of the fourth month of that year - see NYC-5UBTI for the installments.