Even if you don’t know what is a buy back program, at least understand that in most situations it is a good thing. When a company reduces the amount of shares outstanding by declaring a stock buy back program, each of your shares becomes more valuable and represents a greater percentage of equity in the company. Harley-Davidson Inc. (NYSE:HOG) has authorized the buyback of up to 20 million of its common shares, according to a filing with the Securities and Exchange Commission last week. The new repurchase program, which has no dollar limit or expiration date, is in addition to the 6.2 million shares remaining as of Sept. 30 under the October 2006 authorization. It’s also in addition to the ongoing approval to repurchase shares to offset dilution.