Ayvens tracks best day in 15-mths on plans for returns to shareholders

** Shares in Ayvens AYV rise 10.9%, boosted by pre-tax profit beat, a EUR 700 mln share buyback and an exceptional 0.42 euro cash dividend

** Jefferies says that solid capital return with buyback and exceptional dividend is "likely ahead of expectations"

** J.P. Morgan flags pre-tax profit was supported by higher revenues and lower costs and provisions

** JPM adds that it would expect mid-single-digit EPS upgrades to consensus, driven by the strong margin performance and good cost control

** The shares, which sit among top performers on pan-European STOXX 600 index SXXP, are on track for the best day in about 15 months if gains hold

** Up to the previous session's close, they were up 53.7%​ YTD

($1 = 0.8575 euros)