Have you ever wondered why tech companies use blue in their logos? Facebook, Twitter, Samsung, LinkedIn, Intel and IBM all use shades of the color for their entire logos, while Microsoft and Google incorporate it into theirs.

Blue is the “classic king of colors” and appears in more than half of all logos (in any industry), according to research from freelance marketplace 99designs, because it’s a symbol of “trustworthiness and maturity.” The company analyzed 14,000 logos in several sectors including tech, retail and healthcare to understand the psychology of different colors and what they represent.

It is the most popular color in the world in both personal preference and a business context, according to business strategist Anna Lundberg. “It’s a serene and calming color that represents intelligence and responsibility. It’s the go-to color for trusted, corporate institutions,” she stated in a blog on the 99designs website.

Within the tech sector, Microsoft and Google stand out, with both companies choosing several of the same colors in their logos, using green, yellow, red and blue. This mixture shows they have a variety of products as well as communicating action (red), freshness (green), fun (yellow) and security (blue), according to 99designs. The color combination is also used by eBay.

Apple’s logo stands out in tech for its simple monochrome design. But for more than 20 years, its logo was multi-colored, using striped rainbow colors from 1976 to 1998 before its current “luxuriously simple, monochromatic” iteration. And as with other companies, it has strict guidelines on how it can be used by third parties such as resellers, with images of real apples banned, along with words such as Appletree, Jackintosh, or iPodMart.

It’s well-known that Apple co-founder Steve Jobs was a fan of simplicity, telling Businessweek magazine in 1998: “That’s been one of my mantras — focus and simplicity. Simple can be harder than complex; you have to work hard to get your thinking clean and simple.”

Another company that stands out in the tech sector is Snapchat, for its bright yellow logo. Yellow is the color of fun, according to 99designs. Founder Evan Spiegel explained that he chose the color because others weren’t using it. “I drew that on my computer in my dorm room in an evening. When we started to research, we looked at the top 100 apps and noticed that none of them were yellow,” he said during an interview at an advertising event at Cannes, France in 2015.

When it comes to retail, red is by far the most popular color for stores, with 59 percent of industry leaders including it in their logo, such as Staples, Macy’s and PetSmart, according to 99designs. The shade represents passion, anger, vigor and speed, and is used by Target, in contrast to its biggest brick-and-mortar rival Walmart, which uses blue and yellow.

“As opposed to Walmart’s catering (to) ‘everyone,’ Target caters slightly more to younger shoppers—or shoppers who want to feel younger,” according to 99designs.

For corporate industries such as law, the trend for large firms is to have one dominant color and possibly a neutral secondary one. And again, the favoured color for clients is blue, with lighter tones signifying trust and darker ones professionalism, including London firms Freshfields Bruckhaus Deringer and Slaughter and May. They contrast with Baker McKenzie, the largest law firm in the U.S., which uses “two shades of bold and aggressive red” as their branding colors.