DCC Energy’s board falling to the charms of a £5.73 billion (€6.7 billion) bid from KKR and Energy Capital Partners has triggered hand-wringing in the City of London about another FTSE 100 member exiting the best-known national stock index in Europe.The Irish company, which abandoned the Dublin market for London in 2013, is one of several FTSE 100 groups in – or hovering just outside – the departure lounge. It also includes insurer Beazley and investment manager Schroders, who are being acquired by overseas peers, Zurich Insurance and Nuveen respectively; warehouse landlord Segro, which appears to be warming to a takeover by US rival Prologis; and product testing firm Intertek, which agreed last month to be bought by Swedish private equity firm EQT. They follow the likes of former FTSE 100 beasts CRH, Flutter Entertainment, Smurfit Westrock (formerly Smurfit Kappa) and Ferguson moving their primary listings to New York in recent years, before abandoning their London quotations entirely this year. Budget carrier EasyJet, the largest company on the UK FTSE 250 index, would ordinarily be a shoo-in to replace one of the companies currently under offer, were it not itself currently subject to a bid from US investment giant Apollo. Still, there is a host of others primed to take up any slots that fall free on the UK blue-chips index. Oil and gas companies Ithaca Energy and Harbour Energy as well as infrastructure business Balfour Beatty are currently the favourites. If only that were the case in Dublin. The former home market of DCC, CRH, Flutter and Smurfit will not have enough companies to fill the Iseq 20 index by the end of this year, as a steady trickle of market exits looks increasingly like an existential crisis for the Irish equities market. [ How bad would an AI crash really be for Ireland?Opens in new window ]Irish Continental Group (ICG) revealed late on Friday that it has agreed to sell itself to a management buyout team led by its chief executive, Eamonn Rothwell. PTSB’s planned takeover by Bawag of Austria goes before shareholders later this week. Donegal Investment Group, the former dairy processor that is now basically a cash shell, has said it is on track to delist in the coming months. It leaves three spots to be filled by the end of the year. Another Iseq 20 member, Malin Corporation, is also in wind-down.There are only two companies on Dublin’s main and growth markets that could be promoted: Hostelworld and Great Western Mining. Time for Euronext Dublin to do away with the Iseq 20 and replace it with an Iseq 15 or Iseq 10?