The east London club, battling to avoid relegation, acquired South African striker Benni McCarthy, Egypt striker Mido and Brazilian striker Ilan in a bid to boost their prospects of staying up.
They were among the busiest clubs as a slow month of business ended with KPMG's Football Transfer Window Monitor report showing clubs spent just 41.5 million pounds in the month, little more than 20 per cent of the estimated 190.5 million pounds spent a year ago.
The drop in spending was no surprise to financier Paul Miller, the former Tottenham Hotspur defender who specialises in football finances.
"The reason why it is the lowest amount spent in the modern day transfer window is because all the banks have reduced the clubs' overdrafts rather than extend them," Miller told Reuters.
"But whereas two or three years ago a Premier League club could easily have 40 or 50 million pounds overdraft, now its frowned upon. The banks won't allow it and the clubs don't have the money to spend."
McCarthy, 32, joined relegation-threatened West Ham on a permanent deal from Premier League rivals Blackburn Rovers, five years after a planned move to the London club fell through, while Mido signed a four-month deal.
Mido technically moved on loan from Middlesbrough, who hold his permanent contract, although he has been playing for Zamalek in Egypt on loan this season.
Brazilian Ilan, 29, joined the Hammers on loan until the end of the season from St Etienne, with the option of a possible two year deal after that.
MOSES MOVES
In other moves, Wigan Athletic signed Crystal Palace's highly-promising 19-year-old Victor Moses for around 2.5 million pounds and Bolivia striker Marcelo Moreno joined the club on loan from Shakhtar Donetsk.
Former England Under-21 winger, 22-year-old Adam Johnson moved from Middlesbrough to Manchester City on a 4-1/2 year deal for an undisclosed sum.
Stoke City also confirmed on their website they had signed Portsmouth's No.2 goalkeeper, Bosnian international Asmir Begovic, who had a run in the Pompey side when England keeper David James was injured.
Those permanent deals were the only ones confirmed before the 5pm GMT deadline with almost every other deal involving a Premier League club being for a loan period.
"Apart from Manchester City and Real Madrid hardly any money was spent last summer. Now January has followed - very little money spent in Europe, very little spent here, and I think the trend will continue next summer," Miller added.
BUSY SPURS
Harry Redknapp, the manager of Miller's former club Tottenham, was however, busy as usual - but made no permanent deals after signing Younes Kaboul from Portsmouth on Saturday.
Spurs' Scotland international defender Alan Hutton joined Sunderland on loan and young defender Kyle Naughton moved to Middlesbrough until the end of the season.
Ireland international Robbie Keane also left White Hart Lane on loan and went to Celtic, a ye
