Gordon MacIntyre-Kemp, co-founder of the member-owned network, Business for Scotland, said he expects a June poll of SMEs to confirm that they are "ahead of the curve" in their support for independence, compared to the wider Scottish population and larger corporates.
"They are the real wealth-creators and make up more than 90% of the business community," he said.
"Come the referendum I am sure we will have won the business argument and that there will be a majority for 'Yes' both in SMEs and large businesses."
The network claims independence would have positive effects on the whisky and tourism industries, and that international attention on the process would be worth around £800 million in global publicity for the Scotland brand.
Business for Scotland claims to have attracted 500 signatories to its "crowd-sourced" online declaration, which claims that "becoming an independent country means Scotland's economic future will be in Scotland's hands, and that business and economic policies will be tailored to improving productivity and growth, within the distinct Scottish business and economic landscape".
MacIntyre-Kemp compares independence to a "management buyout of a failing branch office".
Business for Scotland advocates lower corporation tax to attract more business headquarters, and promotes the establishment of a Norwegian-style oil-based sovereign wealth fund to "deal with oil price volatility".
He said: "We need to create a business environment where more people can be successful, by boosting the incentives to entrepreneurship, making Scotland a better place with a fairer distribution of wealth."