Every year your basis is increased by contributions, decreased by distributions, increased by profits, decreased bu losses.
IRS provides this way of looking at your K-1 over the years if you need to reconstruct that basis (as so many do at sale time)
A shareholder's stock is increased by ( Form 1120S Schedule K-1 box items):
1. Ordinary incomeBox 1
2. Separately stated income itemsBoxes 2 - 10
3. Tax exempt incomeBoxes 16A & 16B
4. Excess depletionBox 15C
A shareholder's stock basis is decreased, but not below zero, by.
1. Ordinary lossBox 1
2. Separately stated loss itemsBoxes 2 - 12O
and 14L, 14M
3. Nondeductible expensesBox 16C
4. Non-dividend distributionsBox 16D
5. Depletion for oil and gasBox 17R