Donald J. Trump entered the homestretch of the campaign at a pronounced financial disadvantage to Hillary Clinton, according to figures Mr. Trump’s team released on Saturday, and far below the self-funding goal he set for himself earlier in the race.

After raising $100 million in partnership with Republican Party organizations in September, Mr. Trump and committees linked to his campaign began October with $75 million in cash on hand. Mrs. Clinton raised $154 million in September and began October with roughly $150 million in the bank, her campaign said, twice as much as Mr. Trump.

Many of the Republican Party’s leading contributors have stayed away from his campaign, judging from financial disclosures filed by Mr. Trump and his party on Saturday, signaling his difficulties in persuading party elites to back him.

One exception was Peter Thiel, the billionaire Silicon Valley investor who spoke in support of Mr. Trump at the Republican convention in July. A person close to Mr. Thiel said on Saturday that the investor was putting $1.25 million behind Mr. Trump’s campaign.