I feel as though I am too heavy in the SP500 (IVV and SCHB).
I'd like to sell some of these positions, but I don't understand the tax implications of doing so.
What should I be considering?
SCHB is a broad market index with over 2500+ holdings. It is not an S&P 500 ETF, so you might want to keep that.
https://etfdb.com/etf/SCHB/#holdingsAnd here's another idea: instead of selling IVV (S&P 500), invest to balance it out. The S&P 500 is 80% of the market by market cap, so divide your IVV asset value by 4, and that's what you should invest in Vanguard Extended Market ETF (VXF)
https://investor.vanguard.com/etf/profile/vxfIf you have $40k in IVV, that's focused on the S&P 500.
But if you then invest $10k in VXF, that's on the mid/small cap outside the S&P 500
Combine 4 IVV : 1 VXF and you get $50k invested in the total stock market.
That also avoids selling, since it only impacts your new investments.