Companion bill
Definition
A companion bill is a near-identical bill introduced in the opposite chamber at the same time as another bill, so both chambers can consider the same policy in parallel. If one version passes first, it is often substituted for its companion in the other chamber.
Why it matters
Running matching bills in both chambers speeds up passage and gives a sponsor two chances if one version stalls in committee. It also lets interest groups coordinate identical, pre-drafted language across chambers, so the same lobbyist-written text moves through two committee processes with far less independent scrutiny than two genuinely distinct bills would get.
Seen in the wild
In the Texas Legislature, companion bills are common practice: a House bill and its Senate companion are filed with matching text, and if the Senate version passes first, the House sponsor may substitute it for their own bill to save time before the chamber's deadlines.