US consumers were spending their way to the biggest online shopping day ever on Monday, shelling out for products from Barbie dolls to electronics at the start of retailers’ holiday season.

Ecommerce sales were forecast to be at least $12bn on so-called Cyber Monday, when an array of vendors promote discounts online following Thanksgiving and Black Friday sales last week, according to Adobe Analytics.

Economists and investors are watching holiday sales as a gauge of the US economy after months of inflation and rising interest rates have raised the cost of living. Nearly 80 per cent of consumers were looking to “trade down” by swapping planned purchases for cheaper alternatives or forgoing them in their holiday shopping, a McKinsey study found.