What's the fuss about Saudi Aramco and the London market?
The city has been divided about whether the rules for listing on the London Stock Exchange should be relaxed to accommodate Saudi Aramco.
Blockbuster listings create jobs, fees and usually confer prestige on the financial centre that attracts them but in this case, some fear the relaxing of rules to protect minority shareholders undermines its reputation.
The LSE has said that companies come in many forms and London must be flexible enough to accommodate different models and some city folk tell me "let's get real - If we don't do it New York surely will".
Others see it as London, egged on by government, hitching its skirts to attract business to a centre worried that Brexit will make it less attractive than it used to be.
The government has been doing its bit to land this big fish.
In May of this year, Theresa May accompanied the boss of the London Stock Exchange to Riyadh on a charm offensive and one of questions underlying Nicky Morgan and Rachel Reeves' letter to the FCA is whether there was any improper influence exerted on an independent watchdog by government.
When it comes to doing business with the UK, Saudi Arabia has often been seen to play by slightly different rules.
The FCA declined to comment other than say they would respond to the questions in due course.
There were also concerns that the addition of $1.5 trillion company to the London exchange would distort the FTSE 100 index of leading companies making it incredibly oil heavy (BP and Shell are a big component).
Inclusion in that index would force funds that track it to load up on the shares of a company whose corporate structure and governance they didn't like the look of.
That concern looks misplaced as Saudi advisors say they are not seeking inclusion in the index so that anyone buying these shares will be doing it with their eyes wide open.
New York is still considered the favourite in the race for the Aramco listing, but the London Stock Exchange, the regulator and the government are trying very hard to lure it to the UK.
Too hard for some.