Sharecast - At 0855 BST, the FTSE 100 was flat at 7,852.05, as market participants eyed the release of US GDP and initial jobless claims later in the day.
Susannah Streeter, head of money and markets at Hargreaves Lansdown, said: "The FTSE 100 has opened lower, amid uncertainty about the trajectory for the US economy and the knock-on effect worldwide, particularly with banking woes causing so much concern."
In equity markets, Barclays (LON:BARC) was the top performer on the FTSE 100 after saying it was on track to meet full-year guidance, as it posted a 16% jump in pre-tax profits driven by growth across all its businesses. The bank said group income rose 11% to £7.2bn, with pre-tax profit coming in at £2.6bn, generating a group return on tangible equity of 15% and earnings per share of 11.3p.
Matt Britzman, equity analyst at Hargreaves Lansdown, said: "Barclays has posted a very solid first quarter, comfortably beating market consensus on profit amidst a turbulent tie for the broader banking sector."
"It's still early doors for the major UK banks reporting cycle, but signs look promising that issues over the pond aren't leaking into the wider ecosystem. Credit card defaults in the UK remain below pre-pandemic levels, highlighting the UK consumers' resilience despite mounting costs."
"There are some signs of strain in the US, where credit card balances are building. That benefits Barclays, especially in a higher rate environment, but the flip side is higher default rates. It's nothing to get too worried about for now, credit impairments were comfortably within target range, but worth keeping an eye on."
Elsewhere, consumer goods giant Unilever (LON:ULVR) gained as it said that underlying sales growth in the first quarter accelerated to 10.5%, versus analysts’ expectations of 7.5%.
AstraZeneca (LON:AZN) rallied after first-quarter results beat estimates, while London Stock Exchange Group (LON:LSEG), Lancashire Holdings (LON:LRE), and Inchcape (LON:INCH) also rose after Q1 updates.
On the downside, St. James’s Place (LON:SJP), Weir (LON:WEIR), Schroders (LON:SDR), WPP (LON:WPP), and Capricorn Energy (LON:CNE) all fell after updates.
Howden Joinery (LON:HWDN) was also in the red after an update, along with Molten Ventures (LON:GROW), while J Sainsbury (LON:SBRY) nudged lower as it lifted guidance for the current fiscal year after posting a fall in 2022/23 profits.
Legal & General (LON:LGEN), Rightmove (LON:RMV), Relx (LON:REL), and Derwent London (LON:DLN) all lost ground as they traded without entitlement to the dividend.