When looking for penny stocks to buy, I recommend focusing on the basics. That means investing in penny stocks with strong earnings and momentum behind shares. Buying penny stocks that are growing and healthy is crucial, because many low-priced stocks are on the way down — and represent big risks to your portfolio.

Take penny stock Sirius XM (NASDAQ: SIRI ), a low-priced company that is very liquid. SIRI stock has jumped by over +70% so far this year and analysts continue to improve their outlook for Sirius XM. That’s growth you can bank on.

Here are 7 penny stocks, including Sirius XM, that are proving themselves to be great investments right now:

Industry: Computers & Peripherals

Market Cap: $57.3 million

iGo Inc. (NASDAQ: IGOI ) provides products and solutions for the electronics industry, and sells its products through retailers such as RadioShack (NYSE: RSH ) and wireless carriers like AT&T (NYSE: T ).  Since January, iGo’s stock has climbed +42.3%.  This is much better than the broader markets, as the Dow Jones Industrial Average and Nasdaq are up just slightly on the year. iGo has also outperformed analysts’ estimates for the past two quarters by a combined 175%, proving it is healthy and growing.

Harris Interactive Inc. ( HPOL )

Industry: Media

Market Cap: $54.9 million

Professional service firm Harris Interactive Inc. (NASDAQ: HPOL ) provides its clients with market research and polling services.  Its services include customized qualitative and quantitative research, service bureau research and long-term tracking studies.  While this penny stock may be down -15.1% year-to-date, it is up +135% from this date last year.  Additionally, news that Harris Interactive has expanded its Asia sales division has analysts excited, and I’m bullish on HPOL stock as a result.

Spanish Broadcasting System ( SBSA )

Industry: Media

Market Cap: $74.1 million

With 21 radio stations and two television stations in the United States, Spanish Broadcasting System (NASDAQ: SBSA ) is a Hispanic-controlled media and entertainment company.  SBSA also operates LaMusica.com, Mega.tv and websites for each of its radio stations.  In its last income statement, SBSA reported a quarterly revenue growth of +11% year-over-year.  Additionally, the fact that SBSA stock is up +47.4% year-to-date makes this penny stock a strong growth opportunity.

Emmis Communications (EMMS )

Industry: Media

Market Cap: $61.3 million

Emmis Communication Corp. (NASDAQ: EMMS ) is a media company primarily focused on radio broadcasting.  This penny stock owns and operates numerous AM and FM radio stations in major U.S. cities including New York, Chicago and Los Angeles.  Additionally, this media company owns numerous magazines including Texas, Los Angeles and Atlanta Monthly, among others.  With a current stock price of $1.65, Emmis is up +41.6% since the start of 2010.  Likewise, the communication company outperformed analysts’ estimates by 300% last quarter.

Industry: Communications Equipment

Market Cap: $78.3 million

Alliance Fiber Optic Products (NASDAQ: AFOP ) is a designer, manufacturer and marketer of fiber optic components for communication equipment manufacturers.  It also offers numerous interconnect devices including couplers and splitters used to combine optical power. This penny stock has made great strides in 2010 and is up +52.5% against minimal gains from the broader markets in the same period.  Additionally, AFOP has beaten earnings estimates by 100% for two straight quarters.

ICO Global Communications Holdings ( ICOG )

Industry: Telecommunication Services

Market Cap: $496.4 million

Wireless telecommunication service provider ICO Global Communications Holdings Ltd. (NASDAQ: ICOG ) is a development stage mobile satellite service operator.  Despite the fact that ICO has not been able to complete any additional satellites since December 2004, the penny stock has one satellite in orbit, and 10 satellites currently in the production stage.  This penny stock has also boomed in 2010, and has seen gains of 84.3% since January.  Trading at just under $2.00, ICO looks poised to continue its strong year.

Industry: Media

Market Cap: $4 billion

Sirius XM Radio Inc. (NASDAQ: SIRI ) broadcasts music, sports, news, talk, entertainment and weather channels in the United States through its satellite radio systems, for a subscription fee.  Sirius owns both XM Satellite Radio Holdings Inc. and Satellite CD Radio Inc.  Since January, this penny stock has climbed 72.1% and is currently trading at $1.03 per share.  Analysts are projecting Sirius to have a sales growth of 13.4% this quarter, and the satellite radio company has also outperformed earnings estimates two of the last four quarters.

As of this writing, Louis Navellier did not own a position in any of the stocks named here.

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