Pro-union campaigners received more than double the donations given to the Yes camp last month, the Electoral Commission has reported.
Four unionist campaign groups received donations of £151,248 between June 27 and July 24, compared with two nationalist groups which received £65,000, the second pre-poll donations and loans report for the Scottish independence referendum reveals.
Unionists have received a total of £2,657,723 since December 18 compared with £1,524,120 for the nationalists, with both sides boosted by seven figure donations by Harry Potter author JK Rowling and Euromillions winners Chris and Colin Weir respectively in the months to June 27.
The biggest donation last month was £74,747 by JCB digger tycoon and Conservative donor Mark Bamford to the Scottish Research Society, a scientific and literary society campaigning for a No vote. The society was founded in May, and is run by marketing directors Hamish Alldridge and Elaine MacKenzie Grossart.
Official independence campaign Yes Scotland received £40,000 from James H Williamson, plus £10,000 from property developer Alexander W Adam.
Jim Walker, founder of research consultancy Asianomics, donated £10,000 to Wealthy Nation, a right-of-centre pro-independence group founded by historian Michael Fry.
Other notable donors include former Ferranti technologies boss Terry Scuoler, who gave £10,000 to Better Together, and author CJ Sansom who donated £9,000 to the Let's Stay Together campaign which launched with a celebrity video last month.
Let's Stay Together also received £30,000 from Ian Taylor, chief executive of oil trader Vitol and a Tory donor who has previously given £500,000 to the No campaign. He also donated £10,000 to another unionist group called WFS2014.
SNP Westminster leader Angus Robertson said: "This revelation that further donations from Ian Taylor have been accepted by the No camp come at the worst possible time for Alistair Darling.
"Mr Darling can no longer dodge questions about the No camp receiving in excess of half a million pounds from the Vitol boss.
"It reaffirms the fact that while the UK Government punishes vulnerable and disabled people with cruel benefit cuts, Westminster works for the likes of Ian Taylor - no wonder he wants to keep the system exactly as it is, by giving hundreds of thousands of pounds to No.
"The Westminster system works for the few, for people like Ian Taylor - we want an independent Scotland because it will work for the many.
"With a Yes vote, tax collection in an independent Scotland will be made much more effective so that tax which is due is paid, making it fairer for everyone. A No vote would be a win for Ian Taylor, Vitol and tax avoidance.
"We know that Vitol gave the notorious Serb warlord Arkan 1 million US dollars (£593,000). Arkan was indicted by the International Criminal Tribunal for the former Yugoslavia for 'wilfully causing great suffering, cruel treatment, murder, wilful killing, rape and other inhumane acts'. This latest charge of tax avoidance is just the latest episode in the Donorgate story.
"It is unbelievable that the No campaign is happy to accept these funds, and in light of these latest revelations Alistair Darling should at last do the decent thing and hand this donation back. The Taylor money was reportedly personally secured by Mr Darling, and if he does not hand this money back, he is - as a former chancellor - effectively condoning tax avoidance."