Former Birmingham City owners David Sullivan and David Gold are understood to have tabled a £50 million takeover bid - around half of what the club think the east London side are worth.
Sullivan and Gold are reportedly also ready to give manager Zola some £20 million for transfers during the January window to bolster a struggling squad but West Ham's leading shareholder CB Holding has said they are in no hurry to sell.
"You know, we want to keep the best players. I don't know what's going to happen next month," said Zola.
"The only thing I know for sure is that before then we have three games coming up that are very, very important and I want to focus on them. That's the main thing, the rest is out of my control."
The Hammers tackle Portsmouth, the only side below them in the league, on Boxing Day followed by high-flying Tottenham on December 28 and Arsenal in the FA Cup on January 3.
West Ham may be in 19th place but they head into the Portsmouth game on the back of a 1-1 home draw with league leaders Chelsea.
"The first step is get through this game on Saturday which is vital and let's do it all together and then we'll see what happens (in January)," Zola added.
"I can only focus on the game and make sure everything goes well on the pitch. If we keep the same spirit we have against Chelsea I think we are going to go through everything, that is my personal belief."
Defender Danny Gabbidon will miss the Portsmouth game with a hamstring injury but Zola has midfielder Valon Behrami back in contention.