William Ryan Martensen is an enrolled agent and the owner of Martensen Tax & Financial, a firm based in San Juan Capistrano, California, that serves approximately 600 individual and business clients. With more than 15 years of experience in tax preparation, financial planning, and IRS negotiation, Mr. Martensen is recognized as a trusted resource for California taxpayers navigating complex tax obligations. He graduated from the University of Arizona’s Eller College of Business with a bachelor of science in accounting and gained formative early experience under a retired IRS professional. His firm has earned multiple Best Accountant of Orange County distinctions, and Mr. Martensen is known for his ability to simplify the tax code for clients across a wide range of income profiles. He also actively supports his community through charitable golf tournaments and events benefiting youth education and housing.
A tax bill is higher than expected when the amount due exceeds the taxpayer’s planned payment. That surprise often comes from income changes, withholding gaps, nonwage income, or records the taxpayer did not review before filing. It does not automatically mean the return is wrong, but it does mean the taxpayer should pause before treating the balance as unavoidable.
A return reflects more than a filing-day calculation. It compares the year’s tax with payments the taxpayer already made through withholding or estimated payments, then applies credits, deductions, and other return entries. When one part changes, the final balance can change too.
Higher income is one common reason a balance grows. A raise, bonus, commission, investment gain, retirement distribution, second job, or stronger self-employment income can increase the tax owed for the year. Freelance work, gig payments, rental income, interest, dividends, and capital gains can also create a payment gap because these income sources often do not include automatic withholding. For example, a worker who adds freelance income while keeping the same paycheck withholding may not see the shortfall until both income sources appear on the return.
Withholding also matters. Withholding occurs when an employer, pension plan, or other payer withholds tax from a payment before the taxpayer receives the remaining amount. A new job, multiple jobs, marriage, divorce, separation, home purchase, birth, or adoption can change the deduction amounts from each paycheck. When the taxpayer does not update payroll information after those changes, the return may show a larger balance due.
A higher bill can also come from missed credits, deductions, or deductible losses. These items may reduce tax, but the taxpayer needs records to support expenses, losses, or eligibility. Childcare costs, education expenses, retirement savings, dependent-related credits, and deductible expense records can affect the final result when they apply.
After reviewing possible missed items, the taxpayer can compare the current return with last year’s return. That side-by-side review may show changes in income, withholding, filing status, dependents, payments, credits, deductions, or losses. The goal is not to copy last year’s return, but to see which parts changed most.
Sometimes the surprise includes a penalty. If the taxpayer paid too little during the year through withholding and estimated payments, an underpayment penalty may add to the amount due. That charge does not make the situation hopeless, but it shows why tax timing matters before the taxpayer files the return.
Early review can prevent repeat surprises. A taxpayer may need to gather records sooner, watch changing income sources, check withholding after major life changes, or make estimated payments when non-wage income grows. These habits help the taxpayer spot payment gaps before the next balance appears.
Tax professionals vary in credentials, qualifications, and representation rights. A qualified preparer can help trace the balance to return details such as income timing, withholding, estimated payments, or missing support for a deduction. If the issue later requires IRS communication, the taxpayer should understand what role the preparer is allowed to handle. Complete records give the preparer a stronger basis for review and reduce guesswork during the next filing season.
After the taxpayer verifies the return, the better question is what should change before the next paycheck, non-wage payment, or year-end record review. The taxpayer may need to update payroll information, set aside money from nonwage income, or keep proof for deductions as the year unfolds. That turns a larger-than-expected balance into a practical plan for the next filing season.
About William Ryan Martensen
William Ryan Martensen is an enrolled agent and owner of Martensen Tax & Financial in San Juan Capistrano, California. With more than 15 years of experience, he advises approximately 600 individual and business clients on tax preparation, financial planning, and regulatory compliance. Mr. Martensen graduated from the University of Arizona’s Eller College of Business with a degree in accounting and has earned Best Accountant of Orange County recognition on multiple occasions. He is known for his ability to navigate IRS procedures on behalf of clients and for simplifying complex tax obligations into clear, actionable guidance.
Laila Azzahra is a professional writer and blogger that loves to write about technology, business, entertainment, science, and health.