Income taxes are mandatory for people who receive money from a variety of different sources. People with direct-hire employment arrangements benefit from their employers making estimated income tax payments by withholding funds from their checks. Independent contractors and small business owners make quarterly income tax payments.
Taxpayers then file an annual income tax return to confirm how much income tax they owe and reconcile what they paid with the final amount due. Many people receive refunds because they overpay their estimated taxes. Others have to pay taxes because they underestimated their income tax liability.
Even income tax returns can be inaccurate and can result in an underpayment of federal tax obligations if people do not properly disclose all of their sources of income. The three streams of revenue highlighted below are among the most common that people overlook when they prepare their tax returns or estimate their annual tax liability.
Wages from part-time work
The so-called gig economy sees many people working secondary jobs, sometimes for only an hour or two every week. Some people deliver groceries for local stores. Others might moonlight as resellers after purchasing items at garage sales and estate sales. Many people assume that they don’t need to claim these small, secondary streams of income. However, in 2025, any source of revenue that generates $400 or more in income requires reporting and the payment of income taxes.
Revenue from international assets
Many people with international property may overlook their obligation to report income earned in other countries. Whether a domestic taxpayer is a partner in a company operating abroad or has real estate that they rent to tenants in another country, the revenue generated by those international assets requires disclosure on a tax return. Failing to report international streams of income is a common mistake that can have significant consequences for taxpayers. People may need to report and pay income taxes in more than one country in some cases.
Income from digital investments
The various ways that people invest have shifted in recent years. There are now numerous digital or electronic investments that people may acquire in addition to traditional stocks and physical resources, such as gold and silver. People typically have to report any income generated by digital investments, especially if they liquidate those assets. While digital resources are more difficult to track than traditional investments, the IRS does still hold people accountable for reporting these sources of income and paying appropriate taxes on them.
Oversights when reporting sources of income can lead to tax controversies. People may find themselves accused of tax fraud or evasion. They might have to undergo an audit. Reviewing personal resources and revenue streams with a skilled legal team can help those concerned about income tax controversies respond appropriately and avoid the worst possible consequences if they fail to report all of their sources of income on a tax return.