UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K x Annual Report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the fiscal year ended December 28, 2018. OR ¨ Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the transition period from ________ to _________. Commission File Number 0-18655 EXPONENT, INC. (Exact name of registrant as specified in its charter) Delaware 77-0218904 (State or other jurisdiction ...