Cathie Wood of ARK Invest and Rob Arnott of Research Affiliates faced off at Morningstar’s annual investment conference, as recounted in an article in CityWireUSA. The two star managers have vastly different approaches to investing and contradicting forecasts for US stocks, which was apparent in their conversation that was moderated by Morningstar CIO Daniel Needham.

One major source of their clash? Tesla. The EV company is a top holding in Wood’s flagship ARK Innovation ETF and she remains bullish on the stock, explaining that “Tesla is taking a leaf from Apple’s book,” by creating barriers to entry for traditional auto manufacturers. Arnott’s firm, on the other hand, takes the long-view; he congratulated Wood for focusing on disruptors, then added “disruptors get disrupted” in a reference to the Internet bubble.

Wood insisted her firm believes this is the next big wave of valuation and that ARK is “looking forward, not backward,” while Arnott responded, “When you have bubbles, they tend to burst. I view Tesla as a bubble; Cathie does not.”

ARK’s base price target on Tesla is $3000, and Wood indicated that they would peel out of it when that target is hit whether that’s next year or in 5 years. The conversation reiterated the contrasting styles of the two managers, with Wood preferring active management in disruptive companies, while Arnott is a more quantitative investor who drives a series of smart beta strategies.