The Democratic primary election for district attorney in Philadelphia has become a high-stakes contest thanks to the deep pockets of one challenger trying to defeat District Attorney Seth Williams.

Michael Untermeyer, a former city and state prosecutor who is now a real estate investor, lent his campaign $300,000 in 2016, according to campaign finance reports filed Tuesday.

Untermeyer announced Tuesday that he lent his campaign an additional $250,000 on Jan. 4 and raised $90,000 from other donors last month.

Untermeyer raised just $10,025 from other donors in 2016 and spent $36,453.

Untermeyer's self-funding has changed the rules for the primary and general elections. His first donation of $250,000 on Dec. 30 triggered a clause in the city's campaign-finance law that doubled the allowable contributions to $6,000 for individuals and $23,800 for political action committees.

Williams, who is seeking a third term, started 2016 short on cash after closing his previous political action committee at the end of 2015 with just $8,272 and restarting with a new PAC.

Williams reported raising $130,095 for his new PAC in 2016 and spending $55,266, leaving him with $74,829 in the bank as of Dec. 31.

Williams trails in campaign cash three of his four challengers in the May 16 primary, as of Dec. 31.

Joe Khan, a former city and federal prosecutor, reported raising $212,941 in 2016 and spending $2,746, leaving him with $210,195 on hand as of Dec. 31.

Rich Negrin, a former city prosecutor who served as the city's managing director under Mayor Michael Nutter, reported raising $133,665 in 2016 and spending $3,000, leaving him with $130,665 in the bank as of Dec. 31.

Former Municipal Court Judge Teresa Carr Deni, who resigned in December after 21 years on the bench to enter the Democratic primary, reported lending her campaign $35,000. With that loan, Deni raised $44,425 and spent $19,063, leaving her with $25,362 as of Dec. 31.

Beth Grossman, the lone Republican in the race, reported raising $4,700 in 2016 and lending her campaign $17,500. Grossman, who was an assistant district attorney for 21 years, switched her registration from Democrat to Republican in June. She entered the race Jan. 4.

The Inquirer first reported in August 2015 that the FBI and IRS, working with a federal grand jury, had subpoenaed financial records from Williams' previous PAC to examine his personal and political finances.

Williams in August amended his statements of financial interests for 2010 to 2015 to declare $160,050 in previously unreported gifts.

Williams agreed in a settlement with the Philadelphia Board of Ethics two weeks ago to pay a $62,000 fine for not reporting those gifts. That agreement disclosed an additional $15,666 in previously unreported gifts.

In the other contested Democratic primary race in Philadelphia, City Controller Alan Butkovitz reported having $114,220 in the bank as of Dec. 31 as he seeks a fourth term.

Butkovitz started 2016 with $72,653, raised $63,450, and spent $21,883.

He is being challenged by Rebecca Rhynhart, who stepped down in mid-December as Mayor Kenney's chief administration officer. Rhynhart, who also served as city treasurer and then budget director for Nutter's administration, reported raising $32,525 in the final two weeks of 2016 and spending $249.

Joe DeFelice, chairman of the Republican City Committee, said his party was still talking with potential candidates for city controller.