Some of the biggest names in technology have been lavishing millions on Congress during the third quarter, according to government documents — at a time when they’re under increasing regulatory scrutiny from Washington.

The disclosures, required by the Lobbying Disclosure Act, revealed Google spent $4.17 million lobbying Congress this most recent quarter. Facebook spent $2.85 million, while Twitter spent $120,000. The figures were first reported by Bloomberg News.

Last quarter Google spent $5.93 million lobbying lawmakers, while Facebook and Twitter spent $2.38 million and $120,000 respectively.

The three tech titans are sending lawyers to U.S. congressional committees on Nov. 1 to testify on their behalf in response to Russian political ad buying on their platforms during the 2016 election.

The controversy has led to lawmakers calling for more regulation for online ads. On October 19, three senators — Sens. Amy Klobuchar, D-Minn., and Mark Warner, D-Va., and John McCain, R-Ariz. — co-sponsored the bi-partisan “Honest Ads Act.”

The legislation require disclaimers and disclosures to the Federal Election Commission for online political ads. Platforms with 50 million or more unique monthly users would have to keep a public database of political ads, and the companies would have to make “reasonable” efforts to prevent foreign nations from interfering with U.S. elections through ads.

Other tech companies that disclosed large lobbying amounts this past quarter include Microsoft ($1.95 million), Amazon ($3.41 million), Oracle ($3.82 million) and Apple ($1.86 million), among others.