With almost one in two seniors now enrolled in the privatized health plan alternative to traditional Medicare known as “Medicare Advantage,” look for growth to escalate in 2023 and beyond.

Though there have been probes into aggressive marketing practices and other allegations against Medicare Advantage plans, the privatized program has survived myriad examinations by lawmakers and prosecutors and is now one of the more bipartisan policy initiatives in Washington with more than 28 million seniors enrolled in a Medicare Advantage plan in 2022, which accounted for 48% of Americans eligible for Medicare benefits. That growth is projected to only rise for the 2023 plan year.

Health insurance companies that have long been big players in Medicare Advantage, including Humana, Cigna, CVS Health’s Aetna unit, Elevance Health and UnitedHealth Group launched even more plans in several new states and hundreds of new counties for 2023. Meanwhile, smaller startups and regional plans did the same, which is only expected to attract even more seniors away from traditional Medicare to Medicare Advantage.

“There is so much momentum in the sector, a clear and important signal that creating value — meaningful health outcomes and better experiences at lower costs — should be front and center for everyone who is designing and delivering care for consumers,” said John Kao, founder and CEO of Alignment Health, a Medicare Advantage company that has more than 98,000 enrollees in 38 counties across four states.

Alignment, which is completing its first full year as a publicly traded company, continues to draw investors and customers and has been performing well since its initial public stock offering in 2021.

A key to growth are the medical care provider networks that these health insurers create to offer seniors more choices and richer benefits to keep them interested in a Medicare Advantage plans.

Medicare Advantage plans contract with the federal government to provide extra benefits and services to seniors, such as disease management and nurse help hotlines with some also offering vision, dental care and wellness programs. And in recent years, the Centers for Medicare & Medicaid Services (CMS) has allowed Medicare Advantage plans to cover more supplemental benefits, adding to their popularity among seniors.

Given Medicare Advantage plans rely on their relationship with the federal government through CMS, the public-private partnership has flourished despite changing administrations and control of Congress over the last two decades.

Unlike the individual market under the Affordable Care Act that had funding problems and lacked the support of the Donald Trump White House, triggering some health insurers to scale back or hold off on expansion of Obamacare plans, Medicare Advantage has long had political support in Washington among both Republicans and Democrats. That has kept tax dollars flowing to Medicare Advantage and has allowed health insurers to maintain operations and expansions into new regions.

The more established health insurers like Cigna, Aetna, UnitedHealthcare, Humana and Elevance Health are more recently running into competition with regional Medicare Advantage plans and startups have been offering Medicare Advantage.

“People are increasingly selecting Medicare Advantage plans because they offer the kind of choice, convenience and care they’ve longed for in health plans,” Alignment’s Kao said. Effective Jan. 1, Alignment will expand its presence to 52 counties in six states, including the new markets of Florida and Texas.

As newer plans like Alignment continue to grow across the country, more established players have had to up their game by bolstering their benefits offerings and provider networks.

Take Humana, which has long been one of the nation’s biggest providers of Medicare Advantage coverage. Humana earlier this year launched a $1 billion “Project Growth” initiative to strengthen its Medicare Advantage plans for 2023.