It's too late to remove the excess contribution after the 04/15 deadline. You can leave it on the account but make sure that the excess is included in your 2023 income.
Does this have any implications for my situation or are there no options at all after April 15? I am over 59 1/2 and I also filed for an extension on my tax return.
IRC Section 401(a)(30), Section 1.402(g)-1(e)(8)(iii) provides that distributions of excess deferrals after the correction period may be distributed from a 401(k) plan only when permitted under IRC Section 401(k)(2)(B).
Section 401(k)(2)(B)(i) provides that amounts attributable to employer contributions made pursuant to an employee’s election may not be distributable from a profit-sharing plan earlier than (I) the employee’s separation from service, death or disability; (II) an event described in § 401(k)(10); (III) the employee’s attainment of age 59 ½;
or (IV) the employee’s hardship. Events described in § 401(k)(10) include (i) the termination of the plan; (ii) the disposition by a corporation to another corporation of substantially all the assets used by the selling corporation in a trade or business; and (iii) the disposition of a corporation’s interest in a subsidiary.
(III) applies to the EE in question.
Yes, there are some implications. You will be taxed on the amount overcontributed in the year of the contribution. You will also be taxed in the year that the correction is made as well as on any earnings that occur during the year that the overcontributed funds remain in the 401(k) plan account. Be sure to notify your plan that there was an overcontribution in 2023. Since you are over 59 1/2, you will not be subject to the additional 10% early withdrawal tax.
Please see this IRS link for more details.