R&D Tax Credit

Here's the official definition

https://www.enterprise-ireland.com/en/About-Us/Our-Clients/SME-Definition-OJ-2003.pdf

Staff headcount and financial ceilings determining enterprise categories
1. The category of micro, small and medium-sized enterprises (SMEs) is made up of enterprises which employ fewer
than 250 persons and which have an annual turnover not exceeding EUR 50 million, and/or an annual balance sheet
total not exceeding EUR 43 million.
2. Within the SME category, a small enterprise is defined as an enterprise which employs fewer than 50 persons and
whose annual turnover and/or annual balance sheet total does not exceed EUR 10 million.
3. Within the SME category, a microenterprise is defined as an enterprise which employs fewer than 10 persons and
whose annual turnover and/or annual balance sheet total does not exceed EUR 2 million.

The article in the Independent says it will apply to companies with up to 250 employees but that would include Medium Enterprises and there was nothing in the budget to verify that so I don't know where they got that figure

http://budget.gov.ie/Budgets/2020/Documents/Budget/Budget%202020%20Tax%20Policy%20Changes.pdf

Ultimately it will be the Finance Act that will give final detail but it's most likely intended for companies with u to 50 employees.