Chariot, operator of the troubled monday lottery, may have to call in the administrators after plummeting ticket sales fell below break-even level.
Recent attempts to find a buyer have failed. Chariot said that even if it manages to increase ticket sales there is "no guarantee" that this will lead to a successful recovery.
Each of the lottery's 70 charity partners had to pay a registration fee of up to £750. Of these, 64 have benefited from a draw, enabling them to recoup the fee.
However, six of them could end up out of pocket.
Sightsavers, which is among the six, is optimistic it will receive a donation from its first draw on 6 November.
"We need the draw to go ahead if we are to recoup our initial costs," said a spokesman. "We're really hoping monday pulls through."
Chariot's shares fell to 0.2p at the close of business on Friday. But Stuart Hadley, communications director, said: "We are not yet at the point of seeking administration. Our first step is to secure the business."