This dissertation studies two research problems in the field of sourcing.Both topics address sourcing considerations when the buyer’s potential supplier base consists of incumbent and entrant suppliers. The first topic examines when a buyer seeking to procure multiple units of an input may find it advantageous to run a ;;test auction” where she has incumbents bid on a portion of the desired units.The test auction reveals incumbent cost information that helps the buyer determine how many entrants to recruit at a cost prior to awarding the remaining units.The optimal number of entrant suppliers to recruit follows a threshold policy that is monotonic in the test auction’s clearing price unless the underlying supplier cost distribution is not regular.When the buyer uses a reserve price, supplier recruitment can serve as the buyer’s ;;outside option:” If the reserve price is not met in the test auction, the buyer recruits new suppliers and runs a second auction. The attractiveness of the test auction procedure is compared relative to the more conventional approach in which the buyer auctions off her entire demand in one auction. Finally, the optimal mechanism is designed and a numerical study shows that the test with reserve price strategy performs well given its ease of implementation. The second topic surrounds the cost information asymmetry that arises when an entrant competes against an incumbent supplier, and is studied both theoretically and experimentally.The entrant’s cost uncertainty complicates his ability to bid in an auction against an incumbent who is more knowledgeable regarding her costs due to her experience with the buyer.The entrant’s ability to resolve this cost uncertainty by incurring a learning fee is studied. The entrant follows a threshold learning strategy that depends on the nature of the unknown cost distribution.The entrant’s bidding strategy and the buyer-optimal learning fee are analyzed.The experiment shows that subjects understand the basic intuition but tend to under-learn and bid too aggressively when they do not learn prior to bidding; this suggests that buyers need not expend as much effort to reduce the entrant’s learning fee as theory predicts.