Nomura's gamble could well turn out to be a dud. Although it spent only $2 (€1.40, ￡1.35) on the liquidated London-based European operations of Lehman, and $285m on the Asian ones, the purchase – described by Mr Shibata as a once-in-a-generation opportunity to transform his overly domestic “shop” – did not come cheap. In order to retain Lehman staff, many of whom in normal circumstances would never have deigned to work for a domestically focused Japanese bank, Nomura has guaranteed the wages and bonuses of 5,000 bankers for two years at 2007's silly-money levels.

Mr Shibata's expensive leap of faith looks plain stupid to some. It could add $2bn to the Japanese bank's costs when it is already losing money and when rivals are frantically firing people. Nor is it clear whether investment banking margins will ever recover, particularly if the industry reverts, as Mr Shibata suspects, to an old-fashioned merchant banking model in which houses – he calls them “shops” – eschew excessive proprietary trading. If banks gamble less of their own money and return to performing sensible services for more cautious clients, their profits could become distinctly old-fashioned too.

Nor is there any guarantee that, if the good times do return, former Lehman bankers will stick around when their golden handcuffs are unlocked. Why would they, say rivals, want to work for a Japanese bank with a corporate culture alien to Wall Street and with a pitiful network in the all-important US? Furthermore, they ask, what will the merger do to the morale of Nomura's Japanese rank-and-file employees who run the all-powerful domestic brokerage? Must they watch enviously while their flashy new colleagues – from a failed US bank, no less – abscond with several times their own remuneration packages?