Paterson Arran, which employs about 130 people at its Livingston bakery and headquarters, and around 20 staff at Lamlash, on the Isle of Arran, highlighted research published by consumer sector specialist Kantar Worldpanel. It showed its share of the branded shortbread market in Great Britain had surged to 41.4% in the year to December 23, 2012, from 31.4% in the previous 52 weeks.
This jump consolidated Paterson Arran's market-leading position in branded shortbread in the domestic marketplace.
This "branded" category excludes the own-label shortbread of supermarket groups and retailer Marks & Spencer.
In 2007, Paterson Arran's share of the branded shortbread market was little more than 10%.
Looking at the overall shortbread category in Great Britain, Paterson Arran's share climbed to 12.8% from 9.6% by consumer spend, on the basis of the Kantar figures.
Allan Miller, sales and marketing director of Paterson Arran, said his company had overtaken supermarket giant Tesco's own-label shortbread in 2012 to move into second place behind Marks & Spencer, which had a share of 22.7% last year.
The Kantar figures showed that in the Scottish marketplace Paterson Arran was ahead of Marks & Spencer in 2012, accounting for more than £1 in every £5 spent on shortbread.
Paterson Arran's share of the overall Scottish shortbread market in 2012 is put at 21.7%, up from 17.2% in 2011. The market share of Marks & Spencer shortbread is put at 17%.
By volume rather than spend, Paterson Arran's share of the overall Scottish shortbread market is put by Kantar at 37.4%, with Marks & Spencer in second place at 10.6%.
Paterson Arran, which is owned and managed by Alan Hardie and Ian Appleton, was the subject of a buyout from Scotch whisky distiller Edrington in 1995. Mr Miller noted that Edrington retained a small stake in the business.
He said the company dated back to 1895, when it was started by John Paterson and his wife, in Rutherglen.
The bakery was moved to Livingston in 1970, he noted.
Mr Miller said the Paterson family had sold out of the business in the 1970s, and it had gone through changes of ownership.
He added that the Livingston operation was still known as The Royal Burgh Bakery, in recognition of its Rutherglen roots.
Paterson Arran made pre-tax profits of £366,409 on turnover of about £17.5 million in 2011, the most recent financial year for which accounts have been filed.
At Lamlash, Paterson Arran makes jams, chutney, and mustard.