NEW YORK ( TheStreet) -- Berkshire Hathaway ( BRK.B - Get Report) reduced its per share offer for the remaining portion of Charles Munger's Wesco Financial ( WSC - Get Report) on Thursday, a day ahead of a shareholder vote on the deal.

Berkshire lowered the consideration to $385 per Wesco share from $387, according to a company statement.

The statement said the offer was calculated using Wesco shareholders' equity of $386.55 per share as of Jan. 31, 2011, and then adding $4.74 per share to represent Wesco's earnings between Feb. 1 and June 24.

Berkshire then subtracted $6.29 per share for a combination of changes in Wesco investments, dividends already paid and good faith estimates for fees and expenses associated with merger.

In April, Warren Buffett and Munger agreed that Berkshire would purchase approximately 1.4 million shares it does not already own of Wesco, or about 19.9 percent of the company.

Buffett has been a majority shareholder of Wesco, a company that has insurance, furniture rental and steel servicing operations, for more than three decades.

-- Written by Christopher Westfall in New York.