Institutional shareholders were advised to withhold their votes for all nominees to the Coachmen Industries Inc. Board of Directors by Institutional Shareholder Services (ISS), according to a statement issued by Thor Industries Inc. Chairman Wade F.B. Thompson.

Thor is attempting to acquire Coachmen, and because Coachmen’s board has rejected Thor’s unsolicited offer, Thor intends to make the election of members to the Coachmen board a referendum on its acquisition effort.

Thor, which owns 3% of Coachmen’s stock, has not nominated a slate of candidates to compete for votes against the slate of candidates nominated by Coachmen management and directors. Instead, Thor is asking shareholders to withhold their votes.

The vote count is scheduled to be revealed during the Coachmen annual shareholders’ meeting on Thursday in Elkhart, Ind.

Voting by institutional shareholders will be crucial because they own 38% of Coachmen’s stock, according to Coachmen’s proxy statement.

ISS is a unit of Thomson Financial, a business research firm.