The peninsula is heavily dependent on Ukraine for its budget - about 70 per cent, according to some estimates - and for its utilities.
About 80 per cent of Crimea's water and 90 per cent of its electricity is piped in from mainland Ukraine over the narrow neck of land where Russian forces have already established their new border.
Despite speculation, Kiev has refrained from turning off either tap, probably because the country itself is similarly dependent on Russian gas.
Sergei Aksyonov, the pro-Russian Crimean Prime Minister, has promised to replace the Ukrainain currency, the hryvnia, with the Russian rouble by next month.
But no official exchange rate has been set and there are already difficulties with some banks short of cash and many businesses finding themselves unable to accept credit card payments.
Much will depend on Moscow's generosity, which can be capricious.