Premier League clubs have now spent more than £1 billion on transfers in the summer window.
The league had already broken its own transfer record last week, when Manchester City's signing of Barcelona goalkeeper Claudio Bravo pushed clubs' gross spending up to £880 million -- topping the £870m of last summer.
Arsenal completed the signing of Germany defender Shkodran Mustafi from Valencia for a reported fee of £35 million on Tuesday night, which smashed through the £1bn mark with another day of dealing to go.
It is the fourth successive summer that a new record has been set for Premier League spending.
Hull became the 12th club to break their transfer record this window when Ryan Mason moved to the KCOM Stadium from Tottenham.