Tax Questions

Hey y'all, I'm pretty new to the investing scene and had a few questions regarding taxes:

• If I have a stock that lost value but I never realized the loss last year, if it regains value this year and I sell at a break even price, do I owe taxes on it?

• I know about the 3k loss rollover, so I realized 3k in losses last year, but if I sold some stocks I bought last year that are now worth less, can I use those losses to offset any gains I make this year? Or are they just added to the 3k a year tax reduction