It has taken Saied 11 weeks to appoint a new government under Prime Minister Najla Bouden - one essential step towards restarting IMF talks. But he has not yet laid out a plan to restore normal constitutional order as donors demand.
Donors also want Tunisia to set out a series of credible economic reforms, potentially involving subsidies, the public sector wage bill and loss-making state companies, that would curb the deficit and debt.
"The risk of a sovereign debt restructuring has increased, in our view," said Petar Atanasov of Gramercy, a well-known distressed debt fund, saying Tunisia's political problems made it less likely to deliver on reforms needed for an IMF loan.
Market concerns are visible in Tunisia's bond yields - a reflection of how much the government would have to pay to borrow in international capital markets - which have climbed to nearly 16%.
That is more than double what Pakistan has to pay, though it also has a B- credit rating and relies heavily on IMF help, and is much higher than the 9% paid by Ecuador, which has recently defaulted.
"They clearly need to get an IMF programme, rebuild their resources and then tap the market in three years or so," said Viktor Szabo at ABRDN in London, which holds Tunisian debt.
Last week Central Bank Governor Marouane Abassi warned that financing the budget internally carried economic risks including boosting inflation, reducing the bank's reserves and weakening the currency.
"When would there be a failure Nobody has a clear picture of Tunisian finances," said a diplomat in Tunis.
Abassi is emerging as a central figure in efforts to save the economy and is preparing proposals to discuss with the IMF, said the diplomat.
Last week the governor said Tunisia's friends stood ready to help it. But they may have little support to offer without an IMF deal in place.
That would likely require two politically contentious manoeuvres that Tunisia has not yet laid out - an inclusive constitutional roadmap and a set of credible economic reforms.
Saied has brushed aside much of the 2014 constitution and said he can appoint a committee to amend the document and put it to a referendum, adding he would hold a dialogue on it with Tunisians.
So far he has shown little inclination to work with Tunisia's other major political or civil society forces - something that could scupper his chances of getting donors on board.
Recognising his government to the extent of agreeing loan deals without the inclusive process they have called for "would be a complex question", said the diplomat.
Going it alone would also leave Saied without the broad-based support he may need from unions or political parties whose overtures he has so far spurned for the sort of unpopular reforms that could be required for a deal.
His public pronouncements have focused not on readying Tunisians for a looming financial crisis and steps that may be needed to avert it, but on extra money he hopes to raise by tackling corruption.
Successive Tunisian governments have stumbled on the difficulty of agreeing unpopular reforms after a decade of perceived economic decline. To do so now, Saied may have to push aside his apparently unilateral instincts and start working with others.
(Reporting by Angus McDowall and Marc Jones, additional reporting by Tarek Amara; Editing by Alex Richardson) ((firstname.lastname@example.org; Reuters Messaging: email@example.com))