Dr Imthiaz, who signs off as "Proud Premium subscriber" (I like!) dropped me an email last night whose key part reads: "I feel there may be a few more good years ahead for AMZN but can fully understand your rationale for taking profits. What comes next? Perhaps we should look at one of the GINS ETFs or some of the ARK funds? Surely our next Amazon growth story lies in one of those?".Also read: Alec Hogg: Three reasons to consider selling Amazon.Super insights and an excellent reminder of places to look when seeking the next big thing. In past years, I spent thousands of productive hours inputting quarter-end stocks held in unit trusts managed by the likes of Simon Marais, Tim Allsop, Tony Gibson, Roy McAlpine, Piet Viljoen, Peter Major and John Biccard..Keeping track of what was accumulated by superstar managers is a wonderful pointer towards companies worth investigating. Money managers don't share their best ideas – but are forced by regulation to disclose holdings. For instance, filings tell us ARK's superhot manager Cathie Wood (above) is increasing her bets on Zillow and Pacific Biosciences. So well worth us having a gander..___STEADY_PAYWALL___.Also read: Alec Hogg: Mark the dates for our investment conference.On Amazon, I've no criticism of its business model – indeed, rumour has it we're about to see that close up in SA as the ecommerce giant is set to attack Naspers's Takealot. But from the current elevated levels, exponential growth in the share price is asking a lot. So a re-assessment is sensible, particularly as AMZN now accounts for 22% of our portfolio..NB FOR YOUR WALL STREET JOURNAL ACCESS….Because of The Wall Street Journal's credential requirements to access its site, your password MUST be at least 8 characters and include at least one letter and one number; and it MAY NOT contain any special characters (ie #, !, @ etc). To maintain access to WSJ.com, you MUST enter our partner's website at least once a month via BizNews Premium.Sign up now for this webinar….I'm hosting Bright Light Solar's CEO Kevin Shames today noon. It could be your last chance to benefit from the 12J tax incentive which is due to expire at the end of June and from what we hear, won't be extended. Register here: https://attendee.gotowebinar.com/register/1059698724607359500.And for your listening pleasure….Latest audio on BizNews Radio.…..(click on the link to access).Inside Covid-19: Medical breathroughs as common drugs beat cornavirusFB: SA banking shares "have legs"; Mastercard embraces cryptocurrenciesWhat's next for Italitile after it delivers double digit profit, divi growthListed property success story – how Equites is bucking the trendTesla v NIO – battle for electric car dominance in world's biggest marketMeat Naturally: environmentally-friendly SME supporting 2 500 rural jobs