Six FTSE 100 companies go ex-dividend on Thursday 12 November, creating a mechanical drag on the index on the same morning the UK's latest growth figures are published.

Shell, Unilever, Bunzl, GSK, Sainsbury's and Pershing Square Holdings all begin trading without their latest dividend entitlement today, meaning investors who buy from now will not receive the upcoming payments, Kalkine reported.

The six payouts

Shell pays a quarterly dividend of 39.06 US cents, due on 21 December, while Unilever pays 39.07p a share on 18 December. GSK's quarterly payout is 17p, Bunzl's interim dividend is 20.8p, Sainsbury's interim dividend is 4.1p and Pershing Square Holdings pays $0.1837 a share. BP and Airtel Africa also go ex-dividend today, according to dividend calendars.

Why the index feels it

The FTSE 100 is a price index weighted by market capitalisation, so when heavyweight shares such as Shell and Unilever fall by roughly the value of their dividends, the index drops even if nothing else changes. Shell alone carries an index weight of about 6.6%, according to interactive investor.

The cluster is unusually crowded: ex-dividend days rarely make headlines, but six index members going ex on the same morning is rare. A fall in the FTSE 100 today could therefore reflect the dividend adjustments, the reaction to the GDP data, or both.

Shares bought on or after the ex-dividend date do not carry the right to the next payment. Shell's payment date is Monday 21 December, while Sainsbury's pays on Friday 18 December.