We host the final BizNews portfolio monthly update on Tuesday, a little earlier than usual because of the imminent South African holiday shutdown. There's quite a bit to consider, so if you're able to, please diarise the noon starting time. It's a Premium-member only webinar – here's the registration link: https://register.gotowebinar.com/register/5906189847824912656.Read also: Alec Hogg: Piet Viljoen regains his mojo.The most obvious question for Tuesday is what to do about the shareholding in Slack, the disruptive tech company which is the subject of a takeover offer from Salesforce.com. We brought Slack into the portfolio earlier this year via the usual three monthly tranches, completing the purchase in June at an average price of $29.52. The shares adjusted sharply upwards on the bid and now trade at a touch over $42, slightly below the value of the cash plus Salesforce shares offer..___STEADY_PAYWALL___.Although there is always some chance another company will table a counter-bid, in this case it looks unlikely. Primarily because Slack is more valuable to Salesforce.com than to anyone else with either the $27bn ready or desire – Microsoft would love it, but US authorities would veto any suggestion on anti-competitive grounds. Also, at 25 times Slack's annual revenues, the offer price is very full. So we'll be selling the shares on Tuesday..Read also: Alec Hogg: Tesla may be ringing market's bell.A bigger question for the portfolio, though, is whether to consider lightening other holdings ahead of the holiday break – especially after another sensational year for the counters we own. With governments creating cash as never before, right now the opportunity cost of being OUT of share markets looks higher than being invested IN them..TO LISTEN….Latest audio on BizNews Radio.…..(click on the link to access).Deja Vu: McKinsey's SA mea cupla bombs just like in 2018.Discovery's biggest bet – meet Hylton Kallner, new Bank CEO Be kind, business will boom – Faith Popcorn, Foster-PedleyMagnus Heystek: Piet Viljoen has got his mojo back How to generate double digit returns in SA via renewable energyFlash Briefing:Transnet rejects McKinsey R650m State Capture offer.TO WATCH….On the BizNews TV channel on Youtube….Flash Briefing: Stars align for SA equities; more Covid fraud.Finance Friday webinar: Your money after Covid-19Rational Radio webinar: Naspers CFO Basil Sgourdos