NEW YORK ( TheStreet) - When it comes to activists making change in corporate America only one number counts: 5%.

It's the organized 5% of a shareholders that influence management, change the direction of a company or rally the stock with their holdings. It's also the group of shareholders an average retail investor should scrutinize when considering a long-term investment.

On Tuesday, Pershing Square Capital Management's William Ackman sent shares surging nearly 10% when he announced a 15% stake in Fortune Brands Home & Security ( FBHS), signaling he may have been part of a push to spin the unit from its parent Beam ( BEAM), formerly named Fortune Brands.

The announcement followed news on Monday that El Paso ( EP) and its largest shareholder Carl Icahn with a more than 6% holding were bought out by Kinder Morgan ( KMI) at a near 40% premium.

These activists show investors can own shares worth more than a vote in a company's strategy. For the 95% or more of individual shareholders, one share equals one vote.

In terms of returns however, the top 5% don't own all the upside. At Tuesday's Value Investing Congress William Ackman said of his activist holdings, "Our interests are aligned with the investor community in general. It doesn't bother us for 80% of shareholders to come along for the ride." Anyone owning the Fortune Brands', El Paso's or Motorola Mobility's ( KMI) of the investor world may appreciate the idea.

About the keys for a successful activist company plan, Bill Kavaler a special situations analyst at Oscar Gruss & Sons said that a 5% or greater holding is probably needed to really push a management change or company sale. In a phone interview Kavaler said, "For someone with 2-to-3% to say you've got to get your act together and get the stock price up, it's really not that credible." Though 5% gives you an amplified voice, to successfully initiate a company sale, spin or change Kavaler said, "If there is no credible threat and no credible bid, then management won't take it seriously...There are relatively few people that are true activists in that serious sense of the word like Carl Icahn, but even he's got a mixed record."

Consider Icahn's mixed year. On Monday, his third largest holding El Paso ( EP), which has an over 6% share ownership, was bought for $21.1 billion at a near 40% premium by Kinder Morgan ( KMI). Similarly, Icahn took an over 10% stake in Motorola Mobility ( MMI) and asked the company to sell its patents portfolio in the mold of Nortel's $4.5 billion patent sale in July. In August, Motorola Mobility wound up selling itself to Google ( GOOG) for $12.5 billion at a 63% premium --the largest return any investor made on the summer's patent buying spree.

But even with a near 10% share ownership in Clorox ( CLX), a dubious plan got Icahn nowhere in a contest to buy the company, which failed in September. The difference was credibility. In his accumulation of Clorox shares and a roughly $80 a share bid, Icahn said the company could get interest from a competitor at a price of over $100 a share - and bandied around a financing arrangement from Jefferies ( JEF) for $7.8 billion. The company quickly rejected the bid calling it "neither credible nor adequate." When Icahn tried to galvanize shareholders to nominate his slate of board directors, he failed to find requisite support even with a double-digit holding.

In 2010, Ackman, took the investor reins of retail giant JCPenney ( JCP) with a near $1 billion investment that equated to 16.5% of the company's stock. While the 16.5% stake got him a board seat, it's Ackman's activist idea that's given him an edge - potentially one that could have been done at a smaller holding. Ackman was instrumental in hiring star former Apple ( AAPL) retail executive Ron Johnson to run the struggling mid-end retailer. "The decision to hire Ron Johnson was an irrefutable idea," said Ackman at the Congress, showing even with the influence of share ownership, it's the idea that counts.

Ackman's investment, made in 2010 from August through October at levels below $30 a share, has netted him a gain better than the S&P 500 - mainly for the strategic influence his shares bought. With Johnson, Ackman arguably got nearly as big a bang for his $1 billion as buying control in the $6 billion sized retail behemoth. Of his investing strategy, Ackman said on Tuesday, "Without controlling the business, we have a lot of influence."

"The bottom line is I do fundamentally think that every shareholder should have an equal opportunity to voice their opinions," said Scott Rattee a special situations analyst at Stonecap Securities in a phone interview with TheStreet. He nevertheless points that the voice is contingent on its credibility. "One thing I would point to is that if there is an activist with unfounded demands, then the company should be easy to dismiss that," said Rattee.

Smart activist plans may be implemented in short order and be lucrative -even without a double digit holding. In August, Barry Rosenstein run Jana Partners took up a sizeable but not dominant 5.2% partner stake in McGraw-Hill ( MHP) and demanded that the company split itself to maximize the value of its parts. By the end of September, the conglomerate decided to break itself into two publicly traded companies and announced an alliance with CME Group ( CME). McGraw-Hill shares have outperformed the S&P 500 by nearly 10% since Jana announced its holding.

This year Barrington Capital, a smallish hedge fund, took up a fight with offshore oil exploration pipe maker Ameron in January. It won a seat on the company's board and the battle culminated with a July sale of the company for $85 a share to National Oilwell Varco ( NOV), netting a 28% premium to market prices.

For smaller activists without the funds to build close to a 5% holding, there's still optimism. So much so, that last week a small Canadian brokerage Jaguar Financial and miniscule Research in Motion ( RIMM) shareholder put out a highly publicized press release asking the company to find new leadership and consider a sale or split. It seems loudmouthed activists like Jaguar think they can compete with others who wield a heavier financial stick - in its release the brokerage said 8% of shareholders were "supportive" of its plan.

"You can win a proxy contest with a very small number of shares," said Chris Cernich a director of M&A and proxy research at the ISS. He pointed to a 2007 campaign run by Eric Jackson of Ironfire Capital Management and a contributor to TheStreet that successfully coordinated the dismissal of Yahoo! ( YHOO) CEO Terry Semel without a big shareholding. About winning a proxy Cernich added, "Winning a contest is still not going to get you there," --one still has to actually see shares or growth recover.

For the vocal activists like Jaguar, it's still going to be a tough wall to climb to make the activist varsity cut with Research in Motion ( RIMM) without 5% of the company's stock and outright support of shareholders. Jaguar outlined a push for the company to replace its co-founders Jim Basile and Mike Lazaridis with independent heads and split or sell it, yet its chief executive Vic Albioni said in a phone interview with TheStreet, "I don't expect that Research In Motion will respond to our statement." Alboini added, "I think they will expect us to reach out to their directors, which we intend to do now that we have support." Whether intentions turn into actions are up to the 8% of 'supportive' shareholders that would catapault Jaguar into the top 5%.

Right now, the brokerage languishes in the 99% where a share counts for just a vote. About Jaguar's plan released last week, Kavaler of Oscar Gruss said, "If I was an investor, I don't see that there is anything to actually do except to say yes there very well may be value at RIM."

-- Written by Antoine Gara in New York