The weapon sales include a $110-billion deal signed last May when US President Donald Trump visited the kingdom in his maiden foreign visit.
The company's potential market debut, a centrepiece of an ambitious economic overhaul of Saudi Arabia led by Crown Prince Mohammed bin Salman, has drawn the interest of investors around the world - and political leaders hoping to win the listing.
The partnership, announced during the Saudi crown prince's visit to the United Kingdom, includes commitment to work in east Africa, which will in turn strengthen global prosperity.
"From the very time we came until now, we have been able to do our best, and we remain focused on delivering on our promises, " he said.
Instead, she has won no concessions and simply handed on a plate to Saudi Arabia a new humanitarian partnership and an endorsement from DfID [the Department for International Development], the world's best aid agency.
We are all well aware of the gifts that are sometimes showered on a country's worldwide players after they have been successful, but a recent victory by Iraq XI over Saudi Arabia 4 - 1 in a friendly match has led to a remarkable bonus for football in Iraq.More news: Canada aiming to top 16 medals won in Sochi — Going for gold
Prime Minister May defended the two countries' defence ties on Wednesday, saying all arms sales were strictly regulated.
An Aramco IPO was initially slated for 2018 but plans were delayed at least partly because of discussions over where the massive listing should take place. Officials questioned by the paper under strict conditions of anonymity revealed that a doctor and two other people briefed on the condition of the body of Al-Qahtani reported that it had burn marks that appeared to be from electric shocks.
Aside from the logistical support, the USA has been lavishing sophisticated weaponry upon Saudi Arabia since March 2015, when the latter attacked Yemen to restore its Riyadh-allied former government.
The meeting comes as the 32 year-old crown prince seeks to build a defense industry and has been looking beyond the kingdom's traditional Western allies for help.
Downing Street said the framed document was originally created by Queen Victoria's consul general in Jeddah in 1880.