Microsoft has yet to convince Yahoo to agree to a friendly takeover, but the software company is already hiring lobbyists to help it convince regulators to let the deal - hostile if it has to be - go through. Microsoft recently hired Bryan Cave Strategies LLC to lobby the federal government on the proposed multibillion-dollar deal.

The firm disclosed the information on a registration form filed online Tuesday by the Senate's public records office, according to Reuters.

Microsoft announced the unsolicited offer of $31 per share, or more than $40 billion, in February for slumping Yahoo, which rejected the initial bid and is seeking alternatives. Options include an experimental advertising alliance with Google that could lead to a long-term partnership and, according to published reports, a combination with online operations of AOL.

Lobbyists are required to disclose activities that could influence members of the executive and legislative branches, under a U.S. federal law enacted in 1995. They must register with Congress within 45 days of being hired or engaging in lobbying.