The phrase "a vast share" is correct and usable in written English.
It can be used to describe a large portion or significant amount of something, often in contexts related to ownership, resources, or market share.
Example: "The company holds a vast share of the market, making it a dominant player in the industry."
Alternatives: "a large portion" or "a significant share".
It has a vast share of the world's energy.
They came from more than 90 countries, representing a vast share of the global economy.
A vast share of the money given to Mr Gingrich's comes from the family of Sheldon Adelson, a casino tycoon.
Along with Matt Zames, Mr. Cavanagh was tapped to help the bank disentangle itself from a vast share of the positions.
They reflect two of our richest civilizations, two broad religious traditions and a vast share of the world's artistic heritage — and its future.
Shiite politicians and clerics are organizing a unified ballot that will guarantee the majority Shiites a vast share of next month's election spoils at the expense of the country's alienated Sunnis.
A tax exile since the 1970s, Jagger has amassed a vast shares portfolio, and owns properties in the US, the Caribbean and France.
As cloud computing comes of age, our links to one another will be increasingly routed through a vast shared "cloud" of data and software.
O'Reilly is a publisher and a well-known visionary in Silicon Valley who is convinced that the Internet is evolving into a single vast, shared computer, one of whose most important individual functions, or subroutines, is location-awareness.
Even the largest ones still rely on the state for permission to raise capital: Ping An, the second-largest insurer, recently pulled a vast secondary share offering after what was believed to be a quiet word from the authorities.A state-driven financial market means state firms tend to do best.
The vast share of this was acquisitions, but spending on existing businesses grew too, up by 29% over 2006.
