Harris supports tax on unrealized capital gains proposal

Tax targets net worth over $100 million threshold

Proposal faces opposition, questioned for constitutionality

Critics cite issues with valuing illiquid assets

Plan would provide refunds for unrealized losses

Harris aims to build "opportunity economy" for middle class

Investors don't pay taxes until assets are sold

Proposal challenges "step-up in basis" for heirs

Some believe it will limit wealthy tax breaks

Critics worry it might expand to broader groups

Concerns about discouraging startup investment grow

Harris breaks from Biden's capital gains tax rate plan