Most income is taxable, including employment income, refund interest and income from the gig economy and digital assets. When estimating quarterly tax payments, taxpayers should include all forms of earned income, including from part-time work, side jobs or the sale of goods.
Also, various financial transactions, especially those made late in the year, can have an unexpected tax impact that may call for estimated tax payments. Examples include year-end and holiday bonuses, stock dividends, capital gains distributions from mutual funds, and stocks, bonds, virtual currency, real estate or other property sold at a profit.