While you're busy whispering sweet nothings to your partner on Valentine's Day, a handful of companies will be watching the cash roll in.

This year, the average American is expected to spend $134 on the holiday, up slightly from last year's $131 per person, according to the National Retail Federation. In total, that's an estimated $17.3 billion in annual spending on the day.

Many companies, like 1-800 Flowers and Tiffany & Co., will have one of their biggest days of the year today. Here's a look at nine businesses that started the traditions and stand to profit the most.

1-800 Flowers

Founded: 1986

Who invented it: 1-800-Flowers.com CEO Jim McCann

Why it's a tradition: Flowers, particularly red roses, signify love and make affordable gifts. This year, 60% of men and 15% of women are expected to purchase flowers.

1-800-Flowers gets 1 million new customers every Valentine's Day. McCann told CNN his company does about 10% of its annual sales in the run-up to Valentine's Day, but the extra infrastructure that's needed to pull it off raises costs. It hires up to 6,000 extra workers to help with the onslaught of orders for fresh flowers. In the end, he says, it's worth it for the exposure.

The Hershey Company

Founded: 1894

Who invented it: The Hershey Company was founded by Milton S. Hershey and is among the largest chocolate manufacturers in North America. Its headquarters are in Hershey, Pennsylvania, which is also home to Hershey's Chocolate World.

Why it's a tradition: Some claim chocolate is an aphrodisiac due to two chemicals: tryptophan, a building block of serotonin, a brain chemical involved in sexual arousal, and phenylethylamine, a stimulant related to amphetamine, which is released in the brain when people fall in love. Chocolates, then, are fuel for both the mental and physical aspects of romance — which is why lovers offer boxes of them to each other.

Hershey's is an especially popular brand in the U.S., and does particularly well each February 14th. Its stock tends to shoot up right after Valentine's Day, reports Benzinga.

Hallmark Cards

Founded: 1910

Who invented it: Hallmark Cards was founded by Joyce C. Hall, and is the largest manufacturer of greeting cards in the U.S.

Why it's a tradition: The earliest known examples of written Valentine cards are the love letters the imprisoned Duke of Orleans sent to his wife in 1415. Factories began assembling paper Valentines in the early nineteenth century, and greeting card companies started cropping up by the 1850s to meet the demand for Valentine's Day and other holiday cards.

Hallmark creates around 1,400 Valentine’s Day greeting card designs. The company first offered Valentine’s Day cards in 1913 and began producing their own cards in 1916. According to Statistic Brain, 144 million people sent Hallmark cards last Valentine's Day, making it the company's second biggest day, after Christmas.

Necco

Founded: 1847

Who invented it: Daniel Chase, of the New England Confectionery Company (Necco), created "Conversation Candies" in 1866. He built a machine that used a roller pad and text die (pressed against vegetable coloring) to imprint the sayings on the lozenges.

Why it's a tradition: The earliest candies bore messages such as "Married in satin, Love will not be lasting," and "Married in Pink, He will take to drink." The candies were a hit, although it was not until 1902 that short messages were printed on those tiny hearts. Before then they were printed in the shape of postcards, horseshoes, watches, and baseballs.

Necco manufactures 8 billion Sweethearts per year and approximately 100,000 pounds of candy hearts are sold each day during the six-week period between January 1 and Valentine's Day.

Vermont Teddy Bear

Founded: 1981

Who invented it: While playing with his son, John Sortino noticed that all his son's teddy bears were foreign-made. Sortino decided to create his own bears and highlight the fact that they were made in the USA.

Why it's becoming a tradition: It took four days for Sortino to sell his first bear and one year to sell more than 200. Since then, Vermont Teddy Bear has become a multi-million dollar business with hundreds of employees.

Former Vermont Teddy Bear CEO Elisabeth Robert told AllBusiness that men ages 18 to 54 who leave buying a gift to the last minute are one of its top customers. "He comes racing to us, either online or over the phone, to bail him out of a really big problem," she says. "He's willing to fork out $100 on his credit card to have us deliver that gift overnight and solve his problem."

Victoria's Secret

Founded: 1977

Who invented it: Roy Raymond, a graduate of Stanford University's Graduate School of Business, opened the first Victoria’s Secret store at a shopping center in Palo Alto, Calif., in 1977. The idea was to offer a store with a laid-back atmosphere where men would feel comfortable purchasing lingerie for their ladies. 

During its first year in business, the company earned $500,000, and within five years Victoria’s Secret had five stores, a popular catalogue, and a gross income of $6 million per year. Raymond sold the company to Limited Brands in 1982.

Why it's a tradition: Unlike roses and chocolate, lingerie is basically a gift for the guy giving it.

Victoria's Secret holds big sales around the holiday each year as an added incentive.

Tiffany & Co.

Founded: 1837

Who invented it: Tiffany was founded by Charles Lewis Tiffany and Teddy Young in New York City as a "stationery and fancy goods emporium." The store initially sold stationery items and operated as Tiffany, Young, and Ellis in lower Manhattan. The name was shortened to Tiffany & Co. in 1853 when Charles Tiffany took control and the firm's emphasis on jewelry was established. Tiffany & Co. has since opened stores in major cities worldwide.

Why it's a tradition: Almost a third of male shoppers will buy jewelry as a gift this year.

And while Tiffany & Co. does not disclose sales figures for the holiday, it told the Motley Fool that "Valentine's Day is an extremely important occasion for the company."

Armellini Express Lines

Founded: 1945

Who invented it: Jules "Toots" Armellini and his wife Sarah began transporting flowers from Vineland, N.J., into Philadelphia and New York City. They started with one truck and used a barn as their terminal. Eight years later, they moved their corporate headquarters to Florida and now operate a fleet of over 150 trucks.

Why it's a tradition: You have to have some way to move all of those flowers!

Armellini Express Lines, which specializes in floral transportation, starts preparing two months ahead of time and hires dozens of additional trucking operators to help deal with four-and-a-half times its usual volume.

The U.S. Postal Service

Founded: 1775

Who invented it: The concept of a national mail delivery service was established by Benjamin Franklin in Philadelphia, by decree of the Second Continental Congress. The Post Office Department was transformed into its current form in 1971, under the Postal Reorganization Act.

Why it's a tradition: Although postage rates continue to rise, sending a greeting card through the mail is still a relatively affordable way of letting loved ones know you're thinking of them.

Just over half of this year's gift-givers will give out Valentine's Day cards.

Post offices handle 5% to 7% more greeting cards and small packages the week before Valentine’s Day, compared to most other weeks of the year. Valentine's Day is the second busiest time of the year for mailing greeting cards with the USPS, after Christmas.

Now check out some of the best gifts for your Valentine:

20 Valentine's Day Gifts Your Sweetheart Will Actually Appreciate >

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