President Trump's real estate companies' have seen a significant spike in the number of property sales to anonymous buyers over the past 12 months.

Approximately 70 percent of Trump's properties were sold to limited liability companies who conceal buyers' identities while handling the sale, according to a USA Today study released Tuesday.

That number is up from 4 percent of all sales just two years earlier.

Twenty-eight of the companies' 430 properties — valued at $250 million total — have sold since Election Day. Trump made $33 million from the nearly two-and-a-half dozen estates that were sold. The profits go directly into a trust controlled by his adult sons, Eric and Donald Jr. Trump.

Trump entering the Oval Office with a giant business empire has concerned both Democrats and Republicans as they fear foreign or domestic officials could try to bribe Trump by paying more than the valued price for a property or trying to affect him by a different type of compensation.

The study concluded none of the 28 sales went for considerably more than the market value rate.

In January, the Trump Organization hired a corporate ethics officer to oversee real estate deals that may be a conflict of interest for the government.