LONDON — Trian Fund Management, the activist hedge fund run by Nelson Peltz, has acquired a stake in Unilever, according to people familiar with the matter, adding pressure to the packaged food and consumer goods giant in the wake of its failed $68bn bid for GlaxoSmithKline’s consumer-health business.

The size of the stake couldn’t be learned. Trian started buying Unilever shares well before its bids for the GSK unit surfaced earlier this month, one of the people said.