Spring has officially begun, and now may be the time to consider some investments that could add a little "spring" to your portfolio.

Topping the list are companies like Lowe's (LOW) and Home Depot (HD). They stand to benefit from the nicer weather as people head outdoors to work on the garden, plant new beds, maintain the lawn, and take care of home improvements.

What did you think of Home Depot's (HD) earnings report? I rather enjoyed it. And I think the future may be bright for the retailer and arch enemy of Lowe's (LOW).

According to TheStreet.com, net income calculated out to 36 cents per share for the fourth quarter. This was five pennies better than the overall estimate. Same-store sales experienced an increase of 3.9%. And management's forecast for the full fiscal year was upgraded.

Barnes & Noble, the Gap, RadioShack, and Sears -- that may sound like the lineup at the local mall, but in fact they are just a few of the retailers scheduled to step into the earnings spotlight this week. Following last week's disappointing January retail sales numbers from the Commerce Department but strong fourth-quarter reports from Abercrombie & Fitch (ANF) and Nordstrom (JWN), the coming week will offer plenty more data on the sector for investors to mull over.

Walmart

Bentonville-based Walmart (WMT) offered free holiday shipping, closed its Moscow office and named a chief merchandising officer during its fourth quarter. Analysts surveyed by Thomson Reuters forecast earnings for that period to come to $1.31 per share, up from $1.17 in the same quarter of last year. The world's largest retailer also is expected to post revenues of $117.7 billion for the three months that ended in January. That's 3.5% more than a year earlier.

The past week's data-point-of-consequence for investors had to be investment decisions by Warren Buffett's Berkshire Hathaway (BRK.A).

Buffett ended positions in several stocks in the fourth quarter, including the Bank of America (BAC), Nike (NKE), Fiserv (FISV), Becton Dickinson (BDX), Comcast Corp. (CMCSA), Lowe's Co.s (LOW), Nalco (NLC) and Nestle (NSRGY), according to a filing, The Wall Street Journal reported.

Berkshire added to a holding of only one stock in the fourth quarter: Wells Fargo (WFC).

Analyst Upgrades

• Home Depot (HD) to buy from neutral at Goldman.
• Delta Air Lines (DAL) to buy from neutral at BofA/Merrill.
• Heico (HEI) to outperform from sector perform at RBC Capital.
• Royal Dutch Shell (RDS.A) to outperform from neutral at Credit Suisse.
• MB Financial (MBFI) to outperform from neutral at RW Baird.
• Quest Diagnostics (DGX) to equal weight from underweight at Morgan Stanley.
• Oshkosh (OSK) to neutral from underweight at JPMorgan.
• Volterra (VLTR) and Silicon Laboratories (SLAB) to buy from neutral at Roth Capital.
• Ascena Retail Group (ASNA) to overweight from neutral at Piper Jaffray.
• Cytec Industries (CYT) to buy from hold at Deutsche Bank.

Within the first hour of Thursday's session, call volume on Lowe's Companies (LOW) skyrocketed to about 41,000 contracts -- or nearly seven times the equity's expected daily call volume. Checking out the major block trades of the morning, it looks as though a single trader is responsible for much of this option activity.

Specifically, a block of 13,000 contracts changed hands at the ask price of $1.18 on LOW's January 2012 30-strike call, suggesting they were purchased. At the same time, a matching block of 13,000 contracts traded on the equity's January 2012 35-strike call, but these options crossed the tape at the bid price of $0.31 -- indicating they were sold.

Analyst Upgrades

• Walgreen (WAG) and Triumph Group (TGI) to buy from neutral at UBS.
• Focus Media (FMCN) to buy from neutral at Goldman.
• Home Depot (HD) to outperform from market perform at FBR Capital.
• Arbitron (ARB) to overweight from neutral at JPMorgan.
• Waddell & Reed (WDR) and Legg Mason (LM) to overweight from equal weight, and Janus Capital (JNS) to overweight from underweight, at Barclays.
• Central Euro Media (CETV) to buy from hold at Deutsche Bank.
• GenOn Energy (GEN) and Ntelos (NTLS) to outperform from sector perform at RBC Capital.
• Cooper Tire (CTB) to buy from neutral and Goodyear Tire (GT) to buy from underperform at BofA/Merrill.

Starbucks (SBUX) is hosting an investor's conference on December 1. Overall option implied volatility of 30 is near its 26-week average of 32, according to Track Data, suggesting non-directional price movement.

Lowe's (LOW) is hosting its annual analyst meeting on November 30. Overall option implied volatility of 29 is below its 26-week average of 32, according to Track Data, suggesting decreasing price movement.

Update is by Stock Specialist Paul Foster of theflyonthewall.com.

Lowe's (LOW) reported Monday morning that its third-quarter profit was $404 million or 29 cents a share, an increase from $344 million or 23 cents a share a year earlier. Results included charges of two cents and one cent respectively. Revenue climbed 1.9% to $11.59 billion. Same-store sales were rose slightly.

The company had forecast earnings of 28 cents to 32 cents and revenue up 3% to 5%. A year earlier, revenue had declined 3%. Gross margins rose to 35% from 34.2%.

"Home Prices Are About to Bottom" was the headline for the Barron's cover story the week of July 14, 2008. The story explained that the housing market should level off in many areas of the country by the end of the year.

I have made some equally unfortunate prognostications in my tenure at BloggingStocks, so my purpose is not to poke fun at Barron's but to point out that here we are, over two years later, and it is still debatable whether the housing market has bottomed out.

Last week, Macy's (M) and JCPenney (JCP) kicked off the retail earnings season by posting better-than-expected earnings for the most recent quarter. Many more quarterly reports from retailers are due this week, and by and large expectations of analysts surveyed by Thomson Reuters are high.

Walmart (WMT), the king of retailers, is expected to buck the trend, though. Analysts anticipate that the Bentonville-based company will report that its third-quarter earnings grew only 6.7% year-over-year to 90 cents per share. During the three months that ended in October, Walmart announced an acquisition in South Africa and kicked-off the holiday shopping season, and revenue for that period is predicted to have risen 3.0% to $102.4 billion. Looking ahead to the fourth quarter, analysts so far expect sequential and year-over-year growth of both earnings and revenue. Walmart results have not fallen short of consensus estimates in the past five quarters.

Analyst Upgrades

• Standpoint Research upgraded Bank of America (BAC) to accumulate from hold based on valuation.
• UBS upgraded First Solar (FSLR) to buy from neutral and raised its price target to $150 from $136. The firm believes global solar demand will be higher than expected in 2010 and 2011.
• Goldman upgraded Lowe's (LOW) to buy from neutral and has a $24 target on the stock. The firm upgraded shares given the company's margin recovery which will drive EPS growth in 2H10.
• Zep Inc. (ZEP) was upgraded to buy from neutral at Janney Montgomery.
• Rosetta Resources (ROSE) was upgraded to buy from neutral at SunTrust.
• Matrixx Initiatives (MTXX) was upgraded to buy from hold at Roth Capital.

Home Depot (HD), the main rival of Lowe's (LOW), closed higher yesterday by 3.4%, finishing out the session at a price of $28.31. It has a ways to go before reaching the 52-week high of $37.03. Will investors push the stock to that level after the second-quarter report?

I'm not sure that will happen anytime soon, but the data wasn't so bad. Earnings per share grew 9% to 72 cents -- a penny ahead of expectations. Same-store sales expanded by 1.7%.

Lowe's Companies Inc. (LOW), the nation's number two home improvement superstore chain, is scheduled to discuss its second-quarter 2010 financial results Monday, August 16, in a conference call beginning at 9:00 AM (ET) hosted by CEO Robert A. Niblock and CFO Robert F. Hull, Jr. You can catch a live webcast at the Lowe's website.

During the three months that ended in July, Lowe's increased its quarterly dividend. Analysts surveyed by Thomson Reuters expect this Mooresville, N.C.-based company to report earnings of $0.59 per share, up from $0.54 per share in the year-ago period. Its revenue is expected to have risen 4.9% from a year ago to $14.5 billion.

As the earnings season begins to wind down, retail earnings move into the spotlight. Already, JCPenney (JCP), Kohl's (KSS) and Macy's (M) have posted earnings that topped consensus estimates, though the former two also offered disappointing guidance, and Nordstrom (JWN) met earnings expectations.

Many more retailers are scheduled to post their second-quarter results this week, including Walmart (WMT), Abercrombie & Fitch (ANF), and Dollar Tree Stores (DLTR), whose earnings expectations we'll take a closer look at here.