By Naomi Rovnick LONDON, Dec 4 (Reuters) - BlackRock, the world's largest asset manager, expects AI to continue dominating markets in 2026 and anticipates ​a turbulent ride for investors as speculative trading and leverage raise ‌the risks of a repeat of last month's sharp selloff. Helen Jewell, BlackRock's CIO of fundamental equities ‌EMEA, said on Thursday returns from AI-linked investments would stay on an upward trend, with some periods of doubt over sector valuations or outlook that would keep stock ...