Mario Schlosser + Kevin Nazemi + Joshua Kushner found Oscar Health 2012 in NYC as health insurance disruptor targeting ACA individual marketplace launching 2014. Raises $30M Series A from Kushner's Thrive Capital + Founders Fund + others. Bet: tech-first member experience can win ACA exchange enrollees.

Oscar Health Series D Feb 2018 $165M led by Founders Fund + General Catalyst; valuation $3.2B. Mario Schlosser CEO grows Oscar to 250K+ ACA marketplace members across 9 states. Tech-first member app + concierge care team define Oscar's premium retail health insurance experience.

Oscar exits California ACA marketplace Mar 2017 — pulls out of San Francisco + Northern California after losses; refocuses on NY + Texas. Demonstrates ACA marketplace underwriting difficulty for tech-first insurers. Schlosser CEO doubles down on member experience + Cleveland Clinic partnership.

Oscar Health crosses 600K members Q1 2021 — ACA marketplace dominant; +250K from special enrollment period post-COVID. Pre-IPO momentum + Biden administration ACA subsidy extensions drive enrollment. Stock IPO Mar 2021.

Oscar Health IPO Mar 3 2021 at $39/share raising $1.4B on NYSE; market cap ~$8B. First public US health insurtech IPO. Stock immediately falls 11% first day to $34.80; declines to $5 by 2022 amid rising loss ratios + ACA marketplace volatility. Joshua Kushner (Thrive Capital) becomes board chair.

Oscar Health stock crashes 2022 from $39 IPO to $5; medical loss ratios spike to 90%+; founder Mario Schlosser steps aside Apr 2023. Mark Bertolini (former Aetna CEO 2010-2018) becomes Oscar CEO; pivot to disciplined underwriting + risk-adjusted profitability over enrollment growth.

Mark Bertolini becomes Oscar CEO Apr 2023 — former Aetna CEO (2010-2018) joins from retirement. Bertolini's discipline + ACA marketplace tailwind transform Oscar trajectory: medical loss ratio improves from 90%+ to ~80%; ACA enrollment grows. Stock $5 → $20+ by 2025 (4x recovery).

Oscar Health FY2024 — first full-year GAAP profit; Mark Bertolini CEO since Apr 2023. 1.7M+ ACA marketplace members across 18 states. Stock $20+ vs $1.50 trough 2022 (13x recovery). Oscar becomes case study in insurtech turnaround via experienced operator + discipline pivot.

Oscar Health Q3 2025 — Mark Bertolini CEO (former Aetna chairman; CEO since Apr 2023) delivers Oscar's first full-year GAAP profit guidance for 2025. ACA marketplace enrollment grows to 1.7M+ members. Stock $20+ (recovered from $1.50 trough 2022). Bertolini's discipline + ACA tailwind transform Oscar trajectory.