put all your eggs in one basket
/ˌpʊt ˌɔːl jɔːr ˌeɡz ɪn ˌwʌn ˈbæskɪt/
to risk everything on a single venture
“Diversify your investments—don't put all your eggs in one basket.”
Origin: From Don Quixote and American proverb warning against risking everything in one place