(Bloomberg) -- These stocks are no dogs.

With Americans spending like never before on their animalcompanions, stock watchers have been betting on big returns frompet stocks.

The Pet Passion index, a tracker created by Motif Investing thatfollows pet-related companies, has returned 19 percent over thepast year as of Thursday’s stock-market close, sprinting well aheadof the rest of the stock-market pack. The S&P 500 Index hasonly marked an 8.5 percent gain so far this year.

Among the best in show is pet pharmacy PetMed Express Inc.,which has seen its shares nearly double over the past year.Trupanion Inc., which offers pet health insurance, is up about 44 percent inthat span, while IDEXX Laboratories Inc., a veterinary-diagnosticscompany, has gained about 30 percent.

An improving economy has encouraged pet adoptions and loosenedup the wallets of people who already have one, analysts say.Another factor: Younger Americans are putting off having kids butare making room for a dog or a cat.

“Americans sometimes take care of their pets better than theytake care of their own health,” said Mark Massaro, an analyst atCanaccord Genuity Inc. “Americans just love their pets.”

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Pet-related spending in the U.S. is estimated to exceed $69billion this year, up from about $60 billion in 2015 and nearlydouble its level in 2005, says the American Pets ProductsAssociation, an industry trade association. About 90 percent of theestimated 2017 spending is on food, supplies and pet healthcare.

Walking a friend’s dog through Central Park on a recentWednesday, Lisa Alonso Vear, 39, of Brooklyn, quickly whipped outher smartphone to show pictures of her 12-year-old dachshund,Rochester, the way a young mother would normally show off hernewborn.

Vear works at an animal hospital in Brooklyn and said she’s seenan uptick in vet visits -- especially routine checkups -- when theeconomy is strong.

“You’re going to spend money on yourself, but people care a lotabout their pets and care for them and make sure they’re healthy,”she said.

Generation pet

About three in five millennials own pets, according to APPAresearch, compared to about 50 percent of the general population.Meanwhile, birthrates among women in their 20s have dropped morethan 15 percent, according to the most recent data from the UrbanInstitute, a Washington-based think tank.

“Millennials have officially taken over as the primarypet-owning demographic and live out the belief, more than anyone,that their pets are not just pets, but members of their family,”said Andrew Darmohraj, the pet-products association’s chiefoperating officer. “They are willing to spend the money to ensuretheir pets are very much integrated into their lifestyles.”

Paul Columbia, the owner of a New York City-based dog-walkingbusiness, has seen the pet boom close up. He says that his venturehas grown from a one-man-operation in 2001 to 10 employees nowgoing on about 30,000 dog walks a year.

“People are delaying having children and as a result, their petsbecome their children,” said Columbia.

Wagging the dog

The debate around health care for humans, and the uncertaintythat has created for many businesses, also make pet stocks looklike a relative safe haven, one analyst said.

“They’re a very attractive investment for people who want towait on the sidelines until the health-care debate shakes out,”said David Westenberg, an analyst at CL King & Associates. “Youknow what it’s going to look like.”

Republicans have tried -- and failed -- to repeal and replacethe Affordable Care Act, better known as Obamacare, since PresidentDonald Trump took office in January. The Senate is expected to moveon from health care after the August recess to debates about thedebt ceiling, taxes, and other concerns, leaving health care inlimbo.

Investors like the pet market because they can relate to it,said Kevin Ellich, an analyst at Craig-Hallum Capital Group andowner of a 13-year-old wheaten terrier named Ace. Ellich said theindustry trends are positive, and with furry friends continuing tofeel the love, the expectation is shares will continue to grow.

“You probably need a recession to knock down this consistentgrowth,” said Ben Haynor, an analyst at Aegis Capital Corp.

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