Usually, I only give updates on my "World's Greatest Growth Portfolio" at the beginning of each month, along with the three best buys from the group.

Last week, however, was a particularly good one for two of the companies. See the chart below to see how this portfolio has returned 35% since inception, besting the S&P 500 by over 13 percentage points. After that, I'll fill you in on the two companies doing so well.

Core Company
Allocation
Jan. 1 balance
Current balance
Change

Baidu

11.5%

 $115.00

 $111.09

(3.4%)

Google

11.5%

 $115.00

 $127.65

11%

Amazon.com

11.5%

 $115.00

 $120.06

4.4%

Whole Foods

11.5%

 $115.00

 $119.49

3.9%

Tier One

Starbucks

7.5%

 $75.25

 $79.39

5.5%

Apple

7.5%

 $75.25

 $67.57

(10.2%)

Intuitive Surgical

7.5%

 $75.25

 $88.80

18%

IPG Photonics

7.5%

 $75.25

 $75.85

0.8%

Tier Two

3D Systems

5%

 $50.00

 $62.70

25.4%

LinkedIn (NYSE:LNKD)

5%

 $50.00

 $65.50

31%

Stratasys

5%

 $50.00

 $50.85

1.7%

Westport Innovations (NASDAQ:WPRT)

5%

 $50.00

 $53.40

6.8%

Lululemon Athletica

5%

 $50.00

 $44.65

(10.7%)

 

       

Year-to-date

 

 $1,000.00

 $1,067.00

6.7%

Returns Since Inception

     

35%

Source: Fool.com.

So much more than a social network
First on the list of stocks making improvements last week was LinkedIn, which wowed investors by beating earnings per share estimates by 87%, while increasing revenue by an impressive 81%. 

Most important from my perspective was that the company's Talent Solutions division -- the one that has companies paying money to LinkedIn in order to find the top talent for job openings -- increased revenue an impressive 90% from the same time last year, and now accounts for 53% of all revenue.

The market was very pleased, as the stock is up 25% since the announcement of earnings.

Big fleet orders
The other big name from the portfolio making moves last week was Westport Innovations. The company announced that -- along with joint-venture partner Cummins (NYSE:CMI) -- it had received an order from two of the largest public transportation fleets for natural gas engines.

LA Metro and the San Diego Metropolitan Transit System have both signed on for a combined 900 new transit buses for their respective cities. If, however, the options on these contracts are filled in full, Cummins and Westport may be delivering up to 12,500 natural gas engines over the coming years, increasing the national fleet of natural-gas-powered city buses by 20%. 

The company's stock is up about 9% since it made the announcement after market hours last Monday.

Fool contributor Brian Stoffel owns shares of Apple, Google, Amazon.com, LinkedIn, Starbucks, Baidu, Whole Foods Market, Lululemon Athletica, Intuitive Surgical, Westport Innovations, Stratasys, and IPG Photonics. The Motley Fool recommends 3D Systems, Amazon.com, Apple, Baidu, Cummins, Google, Intuitive Surgical, IPG Photonics, LinkedIn, Lululemon Athletica, Starbucks, Stratasys, Westport Innovations, and Whole Foods Market. The Motley Fool owns shares of 3D Systems, Amazon.com, Apple, Baidu, Cummins, Google, Intuitive Surgical, IPG Photonics, LinkedIn, Starbucks, Stratasys, Westport Innovations, and Whole Foods Market and has the following options: Short Jan 2014 $55 Calls on 3D Systems and Short Jan 2014 $30 Puts on 3D Systems. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.