May 20 (Reuters) - The following are the top stories in the Wall Street Journal. Reuters has not verified these stories and does not vouch for their accuracy.

- Authorities trying to locate an EgyptAir plane that disappeared from radar Thursday were battling a lack of concrete evidence and conflicting reports to puzzle out what downed the plane. (http://on.wsj.com/27GdUu1)

- Bayer AG 's offer to buy Monsanto Co, on the heels of two other giant agricultural deals, would put a significant share of the corn-seed and pesticide market in the hands of just three companies, raising concerns among U.S. farmers and legislators about more expensive products and fewer choices. (http://on.wsj.com/27Ge4l1)

- Verizon Communications Inc and others are expected to bid around $2 billion to $3 billion in the auction for Yahoo Inc's core business, less than what the troubled Internet pioneer was expected to fetch, according to people familiar with the matter. (http://on.wsj.com/27Ge8RN)

- Deutsche Bank AG is investigating a series of trades that may have improperly generated millions of dollars in personal profits, some at the bank's expense, for a handful of current and former employees, according to people familiar with the matter. (http://on.wsj.com/27Ge58I) (Compiled by Abinaya Vijayaraghavan in Bengaluru)