Healthy growth in HSA assets. Driven by robust investment growth, HSAs grew to $98 billion in assets held in more than 32 million accounts, a year-over-year increase of 19 percent for assets and 8 percent for HSAs for the period ending December 31.

Strong HSA investment asset growth. With a growing base of investors and continued strong market gains, HSA investment assets rose to an estimated $34.4 billion at the end of the year, up 45 percent year-over-year. On average, investment account holders have a $19,224 total balance (deposits and investments combined).

Participation in HSA investing increases. More than two million HSAs have at least a portion of their HSA dollars invested, representing more than 7 percent of all accounts. HSA contribution and withdrawal growth remains muted. Account holders contributed more than $42 billion to their accounts in 2021 (up 2 percent from the previous year) and withdrew almost $31 billion from their accounts in 2021 (up 2 percent).

Devenir currently projects that the HSA market will reach 38 million accounts by the end of 2024, holding $150 billion in assets.

"Over the past 11 years, health-care consumers have contributed almost $300 billion to their HSAs, used their HSA to pay for over $200 billion in medical expenses and have now accumulated over $100 billion in savings for future medical expenses," said Jon Robb, senior vice president of the company.