Industry sources told the news agency that the announcement of the deal, worth more than US$1.8 billion (RM7.6 billion) at list prices, would be made following a meeting between Donald Trump and Najib, who is visiting the White House at the invitation of the United States president.
The White House says the meeting will focus primarily on security issues and North Korea, and not the corruption scandal.
Prime Minister Najib had once enjoyed close ties with President Trump's predecessor Barack Obama, playing golf with the Democratic president in Hawaii in 2014.
Prime Minister Najib, who has boasted about golfing with President Trump, is less likely to hear about human rights issues from the Republican.
The president is set to host the Prime Minister of Malaysia, Datuk Seri Najib Tun Razak, at the White House Tuesday morning.
Prime Minister Najib founded the fund, which is facing money laundering probes in at least six countries including the United States, Switzerland and Singapore.
Mr Najib said the 9/11 terror attacks not only changed the USA but the world as the assault was inspired by the same "false and poisonous ideology" spread by the global terror network known as the Islamic State in Iraq and Syria ― or its various acronyms ISIS, IS and Daesh.
Malaysia is situated at an important shipping channel, the Straits of Malacca, making it an important ally to both China and the US.
"We are committed to 25 planes of the 737 Max-10, plus eight 787 Dreamliners and there is a strong probability, not possibility" of the purchase of an additional 25 737 Max-10 jets, Najib told Trump.
Also present were Foreign Minister Datuk Seri Anifah Aman, International Trade and Industry Minister Datuk Seri Mustapa Mohamed, Women, Family and Community Development Minister Datuk Seri Rohani Abdul Karim, Malaysian Ambassador to the United States Tan Sri Dr Zulhasnan Rafique and Chief Secretary to the Government Tan Sri Dr Ali Hamsa.
There are about 28,000 Malaysians living in cities throughout the United States.
China is the largest foreign investor in Malaysia, and three Chinese companies are involved in a plan to build a new deep sea port in Malacca costing billions of dollars.
The U.S. Justice Department in June moved to seize more than a half a billion dollars in assets related to the 1MDB case, including a Picasso given to actor Leonardo DiCaprio, the screen rights to two Hollywood movies and a $27 million diamond necklace belong to Najib's wife, Rosmah Mansor.
A senior US official acknowledged it was unusual to meet with Najib while 1MDB was under regulatory scrutiny.