Frederick Darren Berg is scheduled to be sentenced Thursday morning for what prosecutors consider to be the largest Ponzi scheme ever prosecuted in Washington state.

Berg, who ran the Meridian Mortgage investment funds until their August 2010 collapse, has pleaded guilty to one count each of wire fraud, money laundering and bankruptcy fraud. He acknowledged in his plea bargain that investors lost "approximately $100 million," in exchange for a recommended sentence of 18 years.

But final briefs from prosecutors and Berg's defense clashed over how much money was actually lost due to fraud, and when Meridian veered from legitimate business to investment scam. Whether the loss is above or below $100 million will be one factor that U.S. District Court Judge Richard A. Jones considers during sentencing.

The bookkeeping for Meridian's 93 bank accounts was in such disarray that a team of federal and state forensic specialists still can't tell where about $24 million of the firm's deposits originated, or where $3.9 million went.

Prosecutors say investors lost at least $119 million. The defense claims it was less than $100 million, and that a portion of the loss was caused by the real estate downturn, not Berg's unauthorized withdrawals for a Mercer Island mansion, various yachts and jets, and the estimated $45 million he poured into a luxury bus company.