VADIM BELYAEV’S start in business in the mid-1980s was to sell foreign watches on the black market in the Soviet Union. He became a financier, and by 2015 had transformed his bank, Otkritie, into post-Soviet Russia’s largest private lender. Named “Businessman of the Year” by a Russian magazine, he used an English term to describe himself: “Risk-taker”. The risks have caught up with Otkritie. A run on its deposits led this week to its takeover by the central bank (CBR). The rescue is likely to be the largest in modern Russian history. Russian banking has been plagued by lenders with bad loans and inadequate capital, and “pocket” banks that function as money-laundering hubs for influential businessmen. The CBR has embarked on a campaign to clean up the sector, taking on formerly untouchable banks with powerful shareholders and clients. Since 2013 it has shut down more than 300 banks.

Otkritie rose rapidly, out of a small predecessor bank acquired in 2006. It has expanded aggressively, taking over several other lenders, a pension fund and a diamond mine; it has been moving to acquire Russia’s largest insurer, Rosgosstrakh. As Russia descended into recession in 2014, it thrived. It more than doubled its assets through deals to help Rosneft, a state-run oil giant hit by sanctions, refinance dollar loans, and to buy 74% of a Russian sovereign Eurobond issue for 831bn roubles ($14bn). Last year the CBR named Otkritie one of ten “systemically important” banks.

Its troubles began soon after. Rumours about its stability led twitchy depositors to begin withdrawing funds. The process speeded up in July when Russia’s new government-backed ratings agency, Analytical Credit Rating Agency (ACRA), rated Otkritie BBB-, barring it from holding deposits from state companies or pension funds. The collapse in mid-July of Yugra, Russia’s 34th-largest bank, fuelled fears that the CBR’s clean-up campaign would eventually reach Otkritie. In June and July, depositors withdrew some 435bn roubles ($7.4bn), or 18% of Otkritie’s liabilities. The bank took a 330bn rouble loan from the CBR and opened an emergency credit line.

Withdrawals continued and on August 29th the CBR stepped in. It will take at least a 75% stake in the bank and keep it functioning. It chose not to use a recently established mechanism to “bail in” other creditors, nor to revoke the bank’s licence. It reckoned such measures could trigger systemic turmoil. The size of the hole in Otkritie’s balance-sheet is unknown. Some analysts suggest that the failure of Otkritie’s big shareholders—an eclectic and well connected group of oligarchs and state-run companies—to recapitalise the bank at its time of crisis betrays the depth of its woes.

For now, the CBR’s move has halted the panic. “It’s a good precedent that banks don’t have to be closed,” says Oleg Kouzmin of Renaissance Capital, an investment bank. But the rescue will also accelerate the consolidation of assets in the hands of leading, mostly state-owned, banks. Russia’s ten biggest account for some 70% of all banking assets; large state banks make up some 60% (see chart). Otkritie’s troubles may stimulate a further “flight to quality”, says Alexander Danilov of Fitch Ratings. The big will get bigger.