Donors last month gave another $9.6 million to the committee tasked with keeping House Republicans in the majority, according to a summary the campaign arm released Tuesday.

The National Republican Congressional Committee has $42.5 million in the bank, officials said. The committee has now raised more than $101 million to pay for ads, polling and research to help defend GOP incumbents and elect more Republicans.

The House Democrats' campaign arm was expected to release its numbers in the coming days. It has consistently outraised its GOP rivals. As of the end of May, the Democratic Congressional Campaign Committee had outraised its GOP counterpart in 15 of the past 17 months. Not counting its June fundraising totals, the DCCC has raised $113.8 million and has almost $46 million in the bank.

Republicans are expected to hold onto their majority in November's elections. Redrawn congressional districts after the 2010 census heavily favor Republicans, and the party that holds the White House historically has lost seats in elections at this point in a president's term. President Barack Obama, a Democrat, is unpopular in many congressional districts.

Political spending has continued at a rapid clip. The NRCC has booked $30 million in air time ahead of November's elections. Democrats have reserved $44 million in advertising.

House Republicans have 234 seats and Democrats have 199 seats. There are two vacancies.