Schimel is the Waukesha County district attorney and the only Republican in the race. He reported Monday that his campaign raised nearly $367,000 in the first six months of the year and had $400,000 as of July.
Three Democrats are also running.
Democratic state Rep. Jon Richards, of Milwaukee, reported raising $190,000 and having nearly $170,000 cash on hand. Susan Happ, the Jefferson County district attorney, reported raising $170,000 and having nearly $121,000 cash on hand.
The third Democratic candidate, Dane County District Attorney Ismael Ozanne, had not reported any figures as of late afternoon Monday.
The deadline for filing is midnight.