Uggla will be president for now and take over the top job after Steads retirement on Dec. 31 next year.
IHS shareholders will get 3.5566 shares of the combined company for each share held.
The combined company, while maintaining some "key" operations in Colorado, will be based in London.
So-called tax inversion deals have become the subject of a fierce political debate in the United States as well as a source of concern for the government over the potential loss of tax revenue.
"We don't see this transaction as being implicated by the U.S. anti-inversion rules," IHS Chief Financial Officer Todd Hyatt said on a conference call with analysts.
IHS said the combined company was expected to have a tax rate in the low- to mid-20 percent range. IHS's tax rate for the year ended Nov. 30 was 20.5 percent, while Markit paid taxes at the rate of 31.5 percent for the year ended Dec. 31.
The deal is the latest in a string by IHS, whose energy information business, its biggest, has been hit by the slide in oil prices. Revenue in the division fell almost 1 percent to $215.9 million in the first quarter ended Feb. 29.
IHS said in January it would buy U.S.-based Oil Price Information Service to add real-time pricing information to its energy analytics business.
The company agreed in December to buy Canada-based vehicle data provider Carproof Corp. for $460 million to boost its automotive research business.