HITC Sport understands that deals are agreed for the three players and they hope to conclude them all on deadline day.
West Ham have agreed deals for Victor Moses, Nikica Jelavic and Michail Antonio and hope to complete all three by early Tuesday, HITC Sport understands.
Nigerian international Moses is due to arrive on loan from Chelsea with West Ham covering his full wages during that period, although there is still rival interest from a number of clubs including Tottenham.
Moses spent last season on-loan at Stoke City, and he was included in the first-team squad by Jose Mourinho over the summer, but they have now sanctioned another term out on loan - although Chelsea are also expected to announce that he has extended his contract at Stamford Bridge should the loan be finalised..
Championship duo Jelavic and Antonio both will arrive on permanent deals after fees were agreed with Hull City and Nottingham Forest, respectively.
Jelavic has been keen to leave relegated Hull all summer, and HITC Sport revealed at the start of August that West Ham were looking at him. Now the 30-year-old is undergoing a medical at West Ham, where he will be reunited with his former Croatian national team boss Slaven Bilic.
Former Reading star Antonio is also having his medical, after the two clubs finally agreed a deal - and they beat off competition from a number of clubs to land his signature.
HITC Sport understands the deal for Jelavic is just over £1million whilst Antonio is around £7million - all three are due to be confirmed as West Ham players early on Tuesday, ahead of the transfer deadline.