Check your mailbox: The state Franchise Tax Board is busily sending out letters to taxpayers who may owe the state.
The letters, mailed to both individuals and corporations, are part of the FTB's regular audits of the 2012 tax season.
On Monday, the FTB said it sent 100,000 letters to individual taxpayers who may have erroneously filed their taxes this year as "Head of Household." It's also posted a short YouTube video about the HOH status.
It's a commonly misunderstood tax-filing status. "We see a high incidence of error because people don't actually read the qualifications," said FTB spokeswoman Denise Azimi, who said about 2 million Californians claim the HOH filing status each year.
Generally, the HOH status is for single taxpayers who have custody of a child or relative. They get a lower tax rate and a higher standard deduction - $7,682, instead of the regular $3,841 deduction - than someone filing as a regular single.
Last year, the FTB said it collected $26 million in back taxes from 38,000 individuals who had wrongly claimed the head-of-household status.
Also, the FTB is issuing letters to 90,000 California businesses that didn't file a tax return last year for their 2011 income. That's about 10,000 fewer businesses than the previous year, said Azimi, who said the reasons that businesses fail to file are "all over the board," from deliberate to unintentional.
The FTB compiles its list of corporations that didn't file a state tax return by cross-checking income records from the IRS, city business licenses, state Board of Equalization and other sources.
"If you hear from us, please respond quickly and fill out the questionnaires," said Azimi, who said not everyone receiving a letter necessarily owes back taxes. But responding promptly can minimize potential penalties, she noted.