Elon Musk's efforts to arrange new financing that will limit his cash contribution to his $44 billion acquisition of Twitter Inc. have been put on hold because of uncertainty surrounding the deal, people familiar with the matter have said.

Musk has been threatening to walk away from the deal unless the social media company provides him with data to back up its estimate that false or spam accounts comprise less than 5% of its user base. This culminated in a letter from Musk's lawyers to Twitter on Monday warning he may walk away unless more information is forthcoming.

Musk is on the hook to pay $33.5 billion in cash to fund the deal after arranging debt financing to cover the rest. His liquidity is limited given that his wealth, pegged by Forbes at $218 billion, is largely tied to the shares of Tesla Inc., the electric carmaker he leads.