By Spencer Soper Bloomberg Thu., July 19, 2018 SEATTLE—Shoppers spent $4.2 billion during Amazon.com Inc.’s Prime Day sale, up 33 per cent from a year ago, according to estimates from Wedbush Securities Inc. analyst Michael Pachter. The online retailer doesn’t disclose revenue from the 36-hour event that began Monday. Pachter based his estimate on information the company did release, including that it shipped more than 100 million products and that small and mid-sized businesses sold over $1 billion worth of goods in the first 24 hours. Amazon’s web store features its own merchandise as well as products from more than 2 million independent merchants who pay Amazon commissions and fees for storage, delivery and selling on the platform. Pachter’s estimate tops a pre-event prediction of $3.4 billion from Coresight Research and reinforces early projections that Amazon overcame technical glitches that thwarted some shoppers at the start of the sale. Many consumers were disappointed when they couldn’t add products to their carts or their attempts to search for goods prompted an error page featuring dog photos. Read more: Amazon to block Australians from its global websites due to new tax rules Article Continued Below Opinion | Vinay Menon: Amazon is making…