Tagg told BBC Devon: "Our trust members have been down there to help them and give advice."
Argyle risk being wound up next year over a £760,000 unpaid tax bill from HM Revenue & Customs.
"The importance of the trust is that it's the concrete base that the supporters are attached to," added Tagg.
"If [Plymouth fans] become more organised and make themselves have some kind of financial bearing, then they'll have some kind of bearing on the club itself."
Exeter City Supporters' Trust became the majority shareholder of the club in 2003, following the Grecians' relegation from the Football League.
Source: BBC Sport
Source: BBC Sport