West Ham's owners, David Gold and David Sullivan, have sunk a total of £35m into the club since June 2011, according to the club's newly released accounts.

The extent to which the pair gambled on returning to the Premier League at the first attempt was revealed as Gold said he was confident that the saga of the club's move to the Olympic Stadium will be concluded by the middle of this month.

The figures, which cover the year that West Ham spent in the Championship before winning promotion back to the Premier League through the play-offs, show that the club made a loss of £25.5m (excluding one-off costs) in the year to 31 May 2012. The impact of relegation meant a sharp fall in turnover by £34.4m to £46.2m, mainly as a result of a reduction of £26.5m in centrally distributed TV and sponsorship money from the Premier League.

West Ham's net debt now stands at around £70m, but it is understood that the club hopes to wipe out its bank debt of £30.5m within three years if they can remain in the Premier League for that long. They hope to move to the Olympic Stadium by the 2016-17 season and, as tenants, would not be able to secure loans against it. Gold and Sullivan loaned the club a total of £32.2m during the 2011-12 season and the notes to the accounts show they had loaned another £3m by the end of November. The vice-chairman, Karren Brady, said that the group had reduced overall debt to third parties by £10m over the period, but that does not include the money loaned by the owners.

The accounts also show the importance of remaining in the Premier League, estimating that the new £5.5bn TV deal will be worth an extra £15m-£20m to the club per season.

West Ham and the London Legacy Development Company are continuing to negotiate over the fine detail of the move to the Olympic Stadium and Gold said that a deal could be concluded before the LLDC board next meets on 26 March. "I'm embarrassed because I've tweeted 10 times that it's going to be next week or next month and here's a date. The date comes and goes and then I give another date. But I think we are close," he told TalkSport.The accounts show that in September 2012 the club obtained a £12.8m loan against this future season ticket revenue, which it said was to smooth its return to the Premier League. West Ham's executives are confident that they will not have to similarly mortgage future revenues this season.