Source: Sharecast
The FTSE 100 was called to open around 10 points higher.
US President Donald Trump said in a statement that for now, the UK will be spared the 50% tariff that comes into effect on Wednesday. He said he had decided to "provide different treatment" to the UK following the trade agreement struck in May.
The levy for the UK remains at 25%.
Ipek Ozkardeskaya, senior analyst at Swissquote Bank, said: "Today, investors will watch the ADP employment report and ISM non-manufacturing data for fresh insights into US economic strength. Strong numbers may support further gains while soft figures maybe could trigger a pullback.
"Or maybe not. Markets seem to have their own agenda, and the fear of missing a potential rally appears enough to fuel optimism - no matter how weak the forecasts, or the data."
On home shores, the S&P Global services PMI for May is due at 0930 BST.
In corporate news, discount retailer B&M European Value Retail reported a slight rise in full-year earnings against a “challenging” economic backdrop.
Adjusted earnings before interest, tax, depreciation and amortisation rose 0.6% to £620m, while revenue grew 3.7% to £5.57bn.
Elsewhere, real estate group Hammerson announced that its chief executive of five years, Rita-Rose Gagné, has decided to step down from her role in 2026.
Gagné, who was brought on in 2020 to spearhead a strategic transformation of the business, has “driven a substantial turnaround”, according to chair Robert Noel.