Florida Senator Marco Rubio notched a personal best for earnings in 2012 as he and his wife, Jeanette, recorded almost $930,000 in taxable income -- helped by $800,000 that a publisher paid for his best-selling autobiography.

The Rubios set another personal record that year; they incurred more than $11,000 in penalties and interest charges from the Internal Revenue Service, mostly because they paid no taxes on Marco Rubio’s publishing earnings until Oct. 15, 2013, according to documents that Rubio’s presidential campaign provided to Bloomberg News.

Voters wouldn’t necessarily be able to know that from the partial 2012 tax return that Rubio has released, one of 15 years’ worth of partial returns his campaign posted online last month. The 2012 return is undated, and it says the couple made $200,000 in “estimated tax payments” that were due that year. Actually, though, the Rubios filed for a six-month extension on their 2012 tax return, and they paid that $200,000 on the last day of the extension in 2013, according to a pair of tax statements that Rubio’s campaign hadn’t released previously.

Seeking Extensions

It’s not unusual for people to get extensions on filing their federal income taxes; millions do it each year. Yet the IRS requires that they pay their annual taxes -- or a reasonable estimate of them -- by the normal deadline in mid-April or face penalties and interest on any overdue amounts. Rubio has paid such penalties in six of the last seven years, totaling more than $23,000, according to his partial tax returns. The penalty and interest for 2012 represent almost half that total.

Alex Conant, a spokesman for Rubio’s campaign, said in e-mails that the couple has filed for extensions on their taxes, including for 2012. In response to questions, he initially said the couple paid their entire 2012 tax bill -- a balance of $248,171 before penalties and interest -- on Oct. 15, 2013. Later, asked why the return had characterized $200,000 of that amount as “estimated payments,” he said instead that the $200,000 was paid before Oct. 15, 2013, but didn’t specify when. Conant didn’t respond to requests to reconcile his statements.

Rubio, once thought to be the candidate moderate Republicans and the party’s establishment would rally around, has struggled to make inroads in a nominating contest that has been dominated by Donald Trump amid a populist insurgency.

The Florida senator once again performed poorly in key races in Michigan and Mississippi on Tuesday, finishing fourth in both states behind Trump, Texas senator Ted Cruz and Ohio governor John Kasich and picking up zero delegates. So far, he has won only two Republican primaries, in Minnesota and Puerto Rico, and is limping into the make-or-break contest in his home state of Florida on March 15, where Trump holds a large lead in the most recent polling.

In releasing partial tax returns for 2000 through 2014 last month, Rubio became the first of the leading Republican candidates to give voters at least some tax disclosures. Cruz and Kasich followed, but Trump has refused, saying he’ll wait until the IRS finishes an audit that’s under way. The IRS has said taxpayers are free to make their tax returns public, even when they’re under audit.

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