Action Sports with Leigh Roche

Harry Potter author J.K.Rowling gave £1 million to the campaign fighting to keep Scotland in the U.K.

LONDON (CNNMoney)

Harry Potter author J.K. Rowling is on the side of keeping the U.K. together; she gave the "Better Together" campaign £1 million.

And the pro-independence campaign got £1 million from Chris and Colin Weir -- a Scottish couple who won a lottery jackpot of £161 million in 2011.

All told, campaigners opposed to independence have raised £2.7 million in donations greater than £7,500 since December 2013.

The "Yes" campaign raised £1.8 million over the same period.

Those numbers were reported to the U.K. Electoral Commission, which is overseeing Thursday's historic vote.

Related: Scotland's banks threaten to leave

But the final total spent trying to persuade Scotland's 4.3 million registered voters will far exceed the £4.5 million recorded so far by the Electoral Commission.

That's because its figures exclude donations made before December 18, 2013, individual amounts of less than £7,500, and money given to political parties campaigning for either side.

The Weirs, for example, have given as much as £3.5 million in total to support the independence bid.

Related: 5 reasons to worry about Scottish vote

The lead campaign organizations on both sides -- Better Together and Yes Scotland -- were limited to spending £1.5 million each during the 16 weeks leading up to polling day.

But the Scottish National Party of independence champion Alex Salmond may have spent as much as £1.3 million campaigning during that period.

And the three leading British parties opposed to independence were allowed to spend about £1.4 million.

First Published: September 16, 2014: 12:34 PM ET...