DS Smith, Just Eat and Halma join FTSE 100 as reshuffle confirmed

The changes were made after ConvaTec, Merlin and Babcock's market capitalisations fell below the 111th place on the list of the largest companies by market cap by the close on Tuesday, as had been expected. Changes will come into effect on 15 December.

Five companies also dropped out of the FTSE 250 mid-cap index after their shares ebbed lower, with £350m Electra Private Equity bottom of the list and joined by Restaurant Group, Nostrum Oil & Gas, PayPoint and P2P Global Investments.

Replacing them in the FTSE 250 will be RHI Magnesita, the £1.6bn, newly merged supplier of high-grade refractory products, which floated in October; BCA Marketplace, owner of the WeBuyAnyCar.com website; the F&C Global Smaller Companies investment trust; Purecircle, the producer and marketer of stevia sweetening ingredients; and TI Fluid Systems, a manufacturer of automotive fluid storage, carrying and delivery systems that also was an October flotation.

Larger than many of this quintet is Pantheon International, an investment trust that invests in private equity funds around the world and has been growing steadily this year after a strong acceleration in 2016, which in September moved to simplify its dual share capital structure in order to allow its inclusion in the FTSE 250 index in future.