WASHINGTON (AP) -- Mitt Romney's financial portfolio included an offshore company that remained invisible to voters for nearly 15 years.

Bermuda-based Sankaty High Yield Asset Investors Ltd. was not listed on any state or federal financial reports until it was revealed this year in Romney's tax returns. The company is among several holdings that were not fully disclosed, including one that posted a $1.9 million earning -- suggesting he could be wealthier than the nearly $250 million estimated by his campaign.

The omissions were permitted by authorities overseeing the filings, and he has never been cited for failing to disclose information about his money. But tax and legal experts say Romney's limited disclosures deprive the public of an accurate depiction of his wealth and a clear understanding of how his assets are handled.