Highly overvalued 'asml' at ATH has the highest "beta"=~1.73, resulting in the highest downside (systemic) risk among 'aex' funds.
Indeed, following its "beta", when 'aex' is down, for instance, on ~0.9%, the 'asml' should be down "on average" ~1.56% (= 0.9% * 1.73), i.e. very close to that you can see right now (~15.50) from the chart.... (of course, it's just an "average relation" - roughly speaking "systemic risk" - on certain time-horizon, which may deviate at each particular point in time because of stochastic components - for more details just google "beta", and "capm")