The secretive all-party Board of Internal economy has said the so-called "satellite offices" were not a "proper use of parliamentary resources" and on Tuesday authorized that invoices be sent to the MPs to seek reimbursement.
While documents have not yet been released, here's what CBC News can tell you about what the board's decision:
1. 90 days to pay up?
NDP MPs will be sent the invoices and will then have 90 days to respond. Individual MPs could choose to repay the amount or allow the House of Commons to garnish their office budgets, hospitality budgets or their salaries. Of course, given that the NDP has said it plans to fight the matter in court, MPs could also seek an injunction to refuse repayment.
2. Why the bill is $2.75 million
The board considered a number of options to "remedy" the way the NDP used parliamentary resources, including demanding repayment for only this fiscal year, which would have meant the Official Opposition would have been asked to repay $56,492. Instead, the Conservative-dominated board chose to include all salaries dating back to 2011: meaning a total of $2,702,737.
3. Who got the invoices?
A total of 65 MPs will receive invoices. Another three invoices will be divided up between the people who held the positions of party leader, House leader and whip. The leader of the NDP, Tom Mulcair, is also listed separately as a Quebec MP, owing $7,440. The salaries were for a total of 30 staff members.
4. Highest and lowest
The highest invoice for an individual MP belongs to Quebec MP Isabelle Morin. The board claims she owes $169,117. The lowest invoices are for seven Toronto-area MPs who the board is requesting pay back $1,288 each.
5. It's not over yet
The NDP has taken this ruling, and another decision over mailings, to Federal Court. An NDP official says none of the MPs have been given a fair hearing by the board and calls it "smear campaign" and a "kangaroo court." The NDP has pledged to abolish the board entirely and create a non-partisan committee if it forms government.