It is a rare for an auditor to quit the role at a London-listed FTSE 250 firm. So one might conclude it was merely unfortunate that Chris Mawe, the finance director at Ferrexpo, chose last Thursday morning to sell £400,000-worth of shares, just before events moved rapidly at the Swiss-based miner of iron ore in Ukraine. In the evening of the same day, Deloitte quit. On Friday morning, when the firm’s resignation was made public, Ferrexpo’s share price plunged by 28%.

The company had not received Deloitte’s letter of resignation at the time of the share sale, so there is – to be clear – no suggestion rules were broken. Even so, one has to ask if it was sensible for Mawe to sell last Thursday when so many unanswered questions hung in the air.

The quarrel between Ferrexpo and Deloitte had exploded two days earlier when the auditor gave a qualified opinion on the company’s full-year accounts over possible links between Kostyantin Zhevago, its billionaire chief executive and majority owner, and a charitable foundation called Blooming Land. With that row unresolved, and an independent review into Blooming Land’s use of donations from Ferrexpo under way, a wiser board might have ordered a temporary ban on directors’ share dealings.

In the grand sweep of this complicated tale, a £400,000 share sale is perhaps a sideshow. Bigger sums are involved at Blooming Land itself – donations of $33.5m (£26m) in the last two years.

On that score, Ferrexpo on Monday published Deloitte’s explanation of why it resigned: in short, the auditor was frustrated by the company’s delay in commissioning an independent forensic investigation into Blooming Land. For its part, Ferrexpo says it thought a softly-softly approach could be more fruitful, but it came round to Deloitte’s way of thinking in February.

That account raises questions for both sides. Ferrexpo’s initial “cooperative route” seems to have achieved next to nothing, so the board possibly wasted time. But it was also odd for Deloitte to resign two days after the full-year accounts finally appeared, rather than on the spot. In the end, though, everything hangs on what the inquiry produces.

In the meantime, though, the Ferrexpo chairman, Steve Lucas, the former National Grid executive desperately trying to demonstrate commitment to “the highest levels of corporate governance and transparency”, could do himself a favour. If you want to avoid comparisons with ENRC – the dreadful Kazakhstan miner that embarrassed London – tell your colleagues to sit on their shares until the full facts emerge.

Ferrexpo has lost its auditor and two non-executives already. It didn’t need to be answering questions over the awkward, to put it mildly, timing of a director’s share sale.

Failed merger leaves both Deutsche and Commerzbank vulnerable

Merger talks between Deutsche Bank and Commerzbank collapsed last week, to be followed by the inevitable effort by both sides to insist their standalone futures are better than their sunken share prices would suggest. Here comes Paul Achleitner, head of Deutsche’s supervisory board, telling the FT that the troubled investment banking unit does not require a fundamental overhaul.

Achleitner was expressing a minority view, let’s say. To outside eyes, Deutsche is the embodiment of German banking failure, and the investment bank attracts scorn or pity from rivals these days, especially the Wall Street titans. As at Commerzbank, Deutsche’s share price remains more than 90% below its pre-crisis highs.

To get a measure of the decline of German banking, read a blog by David Marsh, the chairman of the Official Monetary and Financial Institutions Forum thinktank (OMFIF) and respected commentator on the German financial scene. The former German chancellor Helmut Schmidt, recalled Marsh, “used to lament how Germany’s giant banking groups would stoke up dangerous enmity among neighbouring countries by inevitably dominating European finance.” Ho, ho.

These days, Deutsche and Commerzbank have a combined market capitalisation of €29bn, versus €83bn for Santander of Spain, €69bn for BNP Paribas of France and €52bn for ING of the Netherlands. Commerzbank is viewed by investors as takeover prey for a foreign bank and, in Marsh’s opinion, Deutsche itself could attract a bid from outside the country.

Either would cause a storm in Berlin, where politicians have generally liked the idea that a German national banking champion would protect German industry in the next financial crisis. But it is hard to see how foreign takeovers could be stopped if everybody is now supposed to be following the same pan-EU banking union script, a point other EU leaders might enjoy making.

“Banking could be the ultimate battleground where Germany must decide between national and European priorities,” says Marsh. “Whatever happens, for Germany this will be painful.” That is a more plausible analysis than Achleitner’s hopeful musings.