Mr. Becker, a venture capitalist who focuses on green technology, raised $110,211 between Jan. 1 and March 17, the second of three campaign finance filing periods. Ms. Kishimoto and Mr. Gordon raised $32,897 and $28,629 over the same period, respectively.
That brought Mr. Becker's total haul since July 1, 2009, to $329,854 as of March 17, according to state filing documents. Mr. Gordon had raised a total of $228,257. Ms. Kishimoto had raised $105,093, and loaned her campaign an additional $85,000.
As of March 17, Mr. Becker had $224,099 left in his campaign fund, compared to Ms. Kishimoto's $92,457 and Mr. Gordon's $82,516.
The three will face off in the Democratic primary elections in June. The winner will be heavily favored to replace Mr. Ruskin, whose term expires at the end of this year.
Mr. Becker was the only candidate to receive quadruple-digit contributions from local residents during the filing period. Atherton residents Sam Bronfman and Peter Week each gave him $1,000, and Portola Valley attorney Marc Gottschalk gave $1,000.
Menlo Park Councilman Heyward Robinson gave $250 each to Mr. Becker and Mr. Gordon. Former Portola Valley Councilman Robert Nielsen gave Mr. Gordon $100.
Mr. Becker's campaign chest was greatly bolstered by sizeable contributions from high-tech executives, including officials from Google, Cisco, Facebook and HP. The Menlo Park resident also received a flurry of large donations from dozens of venture capitalists, lawyers and technologists, including ones his venture-capital firm, New Cycle Capital, has invested in.
Mr. Kishimoto, who served on the Palo Alto City Council for eight years before reaching her term limit last year, earned the bulk of her support from past and present Palo Alto officials, neighborhood leaders, environmentalists, and family members. She also loaned $20,000 to her campaign just before the reporting deadline.
Mr. Gordon, a San Mateo County supervisor, garnered much of his support from Silicon Valley attorneys, construction companies, and labor unions. He also received $3,900 in contributions from Assemblywoman Fiona Ma's campaign, and from the Bay Area Municipal Elections Committee.
—Sean Howell contributed to this report.