In a 1031 exchange, what are the two critical deadlines an investor must meet to defer capital gains taxes?

A valid 1031 like-kind exchange requires the investor to identify potential replacement properties in writing within 45 days of closing the relinquished property, and to actually close on the replacement property within 180 days (or the due date of the tax return including extensions, whichever is earlier). A qualified intermediary must hold the exchange proceeds during the entire process since the investor cannot take constructive receipt of the funds without disqualifying the exchange.