Russia’s financial sector is used to rollercoaster rides. From the immediate post-communist era to the global crash of 2008, via the local 1998 crisis, the volatility of the Russian banking sector has been more or less without parallel.

Today’s tensions over Crimea have yet to lead to much in the way of a direct hit on the banks. US and EU sanctions, freezing the assets of a couple of dozen officials, appear for the time being to be little more than a token gesture. And yet stomachs are lurching among Moscow’s financial elite.

The most obvious signs of nervousness - a tumbling currency, sagging equity and bond prices - are hardly surprising. With heightened political uncertainty about the future of Crimea, Russia’s ultimate goal and the west’s appetite to escalate hostilities, the markets were always going to be jittery.

But the fear among bankers and investors alike is that unless the situation eases, the knock-on effect on the financial sector — and in turn on Russian companies and the economy’s broader growth prospects — could prove far more profound.

The reason is plain enough. Russia’s banking market is more vulnerable than most to disruption, thanks to a combination of relatively under-developed financial structures, rapid recent growth and a high level of dependence on outside money.

In some ways, what has unfolded over the past week or so looks like a mini-replay of the global panic that gripped the whole world’s banking system back in 2007 and 2008.

Even without full-blown sanctions, there has been a two-way rush to erect a barrier around Russia’s financial sector. Russian companies and banks have withdrawn billions of dollars of deposits from US and European banks, fearful that the money could be seized or frozen in the event of tough sanctions.

Likewise, western institutions have been busy minimising their exposure to Russian banks and industrial companies. That has yet to translate into outright ostracism - credit lines remain open, for example. But there have been examples of ‘risk mitigation’, to use a favourite banker euphemism. Barclays last week pulled out of a project with VTB, Russia’s second-biggest bank, to jointly finance an Essar Energy deal in India.

It would not take much for such jitters to spread to a wholesale withdrawal by western banks from working with Russian counterparties.

Back in 2007-08, the global crisis exposed the cavalier way in which multiple banks — from Lehman Brothers in the US to Northern Rock in the UK — had financed themselves. Without access to bond markets and interbank finance they were sunk.

VTB and Sberbank, Russia’s biggest lender, are no clones of Lehman or Northern Rock. They are diversified global operators, with a mix of retail and investment banking and some strong management.

But in the crucial zone of their funding structure, there are parallels with many of the western banks that expanded aggressively in the run-up to the crisis on the basis of financing that proved horribly fickle when push came to shove.

Both VTB and Sberbank were already hefty banks back in 2009. Today they are twice the size. At the same time as western lenders have gone through a painful process of reversing their boom-time credit expansion, Russia’s twin banking giants have seen their balance sheets balloon both at home and abroad.

At the last count, in September, VTB’s assets were about Rbs8.5tn ($236bn), up 13pc since January 2013. And although such rapid growth has been financed largely by increased customer deposits, those funds still cover barely half of the bank’s asset exposure — an unusually small proportion by post-crisis global standards. That means the bank is heavily dependent on funding from the capital markets - a problem if the capital markets are shut, as they are currently.

A similar balance sheet structure, though in less extreme form, is evident at Sberbank.

There is a silver lining to the cloud of the Crimean crisis. Call it nervousness. Call it patriotism. But within only a week or two, Russian companies have repatriated as much as $50bn by some estimates. Money that was once a funding resource for western banks is now valuable finance for VTB and Sberbank.

At the same time, Russia’s central bank has made it clear to local financiers that it is prepared to reactivate a suite of mothballed liquidity facilities made available at the height of the 2008 crisis.

So Russia’s banking system is not about to go under. But banks and companies will undoubtedly find life tougher, at least in the immediate future — access to the capital markets, when it returns, will be more expensive; and the inflationary pressures that could result from central bank intervention will compound problems in the meantime.

Ultimately, though, as long as the Crimean crisis is contained, fans of Russian finance will probably not be deterred - the latest plunge in the sector’s fortunes is just another freaky fairground ride.