As BofA’s stock fell, along with the stock of almost every other bank around, the biggest loser was Lehman Brothers. Accustoming themselves to cheaper mayonnaise in their canteen turned out to be the least of the worries of employees of a bank that has now filed for bankruptcy: the holding company has aimed at Chapter 11; the remainder at Chapter 7.

The filing includes a request to continue paying salaries to employees, part of a series of first day motions that will “allow it to continue to manage operations in the ordinary course”. Whether shareholders, bondholders and investors in structured products will be as fortunate remains to be seen.

Merrill can consider itself lucky. It has long been courted by BofA, but had been suffering a mighty hangover from its sub-prime exposure – as FT research showed in August, the last eighteen months have seen the bank undergo writedowns and credit-related losses of nearly $52bn: half of its profits over the past 36 years. But BofA itself has not been immune to the market crisis, selling its equity prime brokerage division to BNP Paribas in June.

The frantic weekend could have many consequences for the structured products world, not least in the UK, where around 25% of product is understood to have been issued by the now-failed US bank.

Lehman’s disappearance, although troubling and likely to shake investor confidence over counterparty risk even further, may remove a thorn in the side of structurers at other better rated banks. For months, structurers across Europe have complained that Lehman has frozen primary market volumes, as its lower credit rating enabled the bank to sell products with more attractive coupons. Investors still wanted the same coupon, but not the risk of Lehman paper, which created a much tougher context for other banks selling products. Bear Stearns, a week prior to its collapse, was offering reverse convertibles with a 27% contingent coupon after 18 months, which perhaps proves the same adage – if the deal seems too good to be true, then it probably is.

The ethos of Lehman’s US business was “not all structured investments are created equal.” The slogan has proved a rather sad prophecy for the bank and its structured product investors. By coincidence it also happens to be the tagline for the new ETF i-shares advertising campaign – let’s hope the company experiences the more positive intended consequences of the marketing strategy.

The Merrill acquisition on the other hand, will leave its competitors with little room to relax, creating a banking behemoth worth just over $200 billion. This year’s other monster merger, JP Morgan and Bear Stearns, creates a bank valued at $141.5 billion, leaving Goldman Sachs ($60.73bn) and Morgan Stanley ($41.29bn) looking like mere minnows.

Tomorrow evening will see BofA receive a bevy of journalists at Tate Britain for Francis Bacon: A retrospective, which the bank is sponsoring. Perhaps it is to witness a lap of victory round the gallery by the no doubt jubilant hosts, or simply to gaze upon Three figures for the base of a crucifixion and ponder what lies in store for the now few pure investment banks that remain.