Premier League clubs have spent an estimated £300m during the first week of the summer transfer window.
By comparison, £870m was spent during the nine weeks of last summer's window.
Business analyst Deloitte expects gross outlay to rise above £1bn before the window closes on 31 August.
A new £5bn three-year television deal, which starts this season, is fuelling "unprecedented" spending amid "unreal" player valuations, football finance expert Rob Wilson told BBC Sport.
"There's no questioning the impact of the TV deal," added Sheffield Hallam University's Wilson, who said he had expected spending in the first week of this summer's window to be even higher.
Each club can expect to receive between £30m and £50m from the Premier League for 2016-17 as a result of the TV contract, under which Sky are paying £4.2bn and BT £960m for the rights to show live top-flight matches over the next three seasons.
Wilson believes that is driving player values through the roof. "We've seen this trend, over the last two or three deals at least, but we never thought the valuations would go up that much. It's unreal," he said.
The combined total spent by Premier League clubs over the summer and winter transfer windows last season was £1.045bn - up from £965m for 2014-15.
BBC Sport based its own estimate on actual fees announced by clubs and on reported figures when the value of a transfer has been undisclosed.
Where has the money been spent?
Manchester United have been among the biggest spenders, reportedly paying £26m for Borussia Dortmund attacker Henrikh Mkhitaryan and £30m for Villarreal defender Eric Bailly.
Neighbours Manchester City bought Dortmund midfielder Ilkay Gundogan for a reported £20m, and also spent an estimated £13.8m on Celta Vigo winger Nolito.
Liverpool, one of the biggest gross spenders in 2014-15, paid £34m for Southampton forward Sadio Mane this summer. That deal was announced in late June but clubs can only complete the transfers and register players from 1 July onwards, when the window opens.
Champions Leicester have broken their transfer record with a £16m deal for CSKA Moscow striker Ahmed Musa, and have also brought in midfielder Nampalys Mendy from Nice for a reported £13m and German goalkeeper Ron-Robert Zieler from Hannover 96.
Even clubs promoted from the Championship have spent heavily. Middlesbrough can count Denmark international winger Viktor Fischer, signed from Ajax, among their new arrivals, while midfielder Marten de Roon was signed from Atalanta for a reported fee of around £12m.
In recent seasons, more - and bigger - deals have been completed during the second half of a transfer window, analysts say.
"As we go through the window, some other teams respond, such as Arsenal, Chelsea, Manchester City," Wilson said.
"Prices go up quite sharply. With the European Championships finishing, players such as Antoine Griezmann will see their value increase, because of his performances and the valuation of the TV deal."
France international Paul Pogba, for example, has been linked strongly with a £100m move to Manchester United, the club he left in 2012. His agent, Mino Raiola, also represents Mkhitaryan and another of United's summer signings, Zlatan Ibrahimovic.
It is thought a number of clubs have shown interest in Juventus midfielder Pogba and, if he were to move to the Premier League, the 23-year-old would be likely to command a fee in excess of the world record £85.3m Real Madrid paid to Tottenham Hotspur for Gareth Bale in September 2013.