In a statement, the North London club said 40.9 million pounds had been spent on signing Lukas Podolski, Santi Cazorla and Olivier Giroud and extending the contracts of players including England internationals Theo Walcott and Jack Wilshere.
Player sales netted 42.5 million while turnover dropped from 113.5 million pounds to 106 million as a result of four fewer home fixtures compared to the same period in the previous year.
The profit for the six months to November 2011 included the sale of Cesc Fabregas, Samir Nasri and Gael Clichy.
Arsenal, which is majority-owned by American Stan Kroenke, said it had no short-term debt and possessed cash reserves of 123.4 million pounds compared to 115.2 million a year earlier.
"Our ability to compete at the top of the game here and in Europe is underpinned by our financial performance which gives the club strength and independence," chairman Peter Hill-Wood said.
Arsenal fans have become increasing frustrated by their team's failure to win a trophy since the 2005 FA Cup and have urged manager Arsene Wenger to spend freely on buying top-quality players to replace Fabregas and Robin van Persie, who was sold to Manchester United last year.
The club were knocked out of the League and FA Cups this season and they lost their Champions League last 16 first leg 3-1 at home to a clearly superior Bayern Munich side.
Wenger, whose contract expires at the end of next season, gained some relief at the weekend when his side defeated Aston Villa 2-1 in the Premier League after losing to Bayern Munich and being knocked out of the FA Cup by Blackburn Rovers.
Arsenal are fifth in the Premier League behind London rivals Tottenham Hotspur, one place off a Champions League spot. They play Tottenham at White Hart Lane on Sunday.
