UNITED STATES ~~SECURITIES~~ ~~AND EXCHANGE COMMISSION~~

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT ~~PURSUANT~~ ~~TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934~~

~~Date~~PURSUANT ofTO ~~Report~~SECTION 13 ~~(Date~~OR ~~of earliest event reported~~15(d): OF ~~July~~THE ~~28, 2011~~

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): December 19, 2011

NATIONAL PROPERTY INVESTORS 4

(Exact name of registrant as specified in its charter)

CALIFORNIA	0-10412	13-3031722
(State or other jurisdiction	(Commission	(IRS Employer
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)
of incorporation)	File Number)	Identification No.)
55 BEATTIE PLACE POST OFFICE BOX 1089 GREENVILLE, SOUTH CAROLINA		29602
(Address of principal executive offices)		(Zip Code)

55 BEATTIE PLACE
POST OFFICE BOX 1089
GREENVILLE, SOUTH CAROLINA		29602
(Address of principal executive offices)		(Zip Code)

Registrant’s telephone number, including area code (864) 239-1000

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

þx Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

¨	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

ITEM 1.01. Entry into a Material Definitive Agreement.

OnAs ~~July~~previously 28disclosed, ~~2011,~~ National Property Investors 4, a California limited partnership (“NPI 4”), ~~entered~~ ~~into an agreement and plan of conversion and merger (the “Merger Agreement”) with~~ AIMCO Properties, L.P., a Delaware limited partnership (“AIMCO OP”), and AIMCO NPI 4 Merger Sub LLC, a Delaware limited liability company of which AIMCO OP is the sole member (the “Merger Subsidiary”), ~~pursuant~~ toentered ~~which~~into ~~the~~an ~~partnership~~Agreement ~~agreement~~and Plan of ~~NPI~~Conversion ~~4 will first be amended to remove the~~and ~~prohibition~~Merger, ondated ~~transactions~~as ~~between~~of ~~NPI~~July 28, on2011 (the ~~one~~“Merger ~~hand and its general partner and its affiliates~~Agreement”), onpursuant ~~the~~to ~~other, following~~ which NPI 4 ~~will~~would be converted from a California limited partnership to a Delaware limited partnership named National Property Investors 4, LP (“New NPI 4”), following which the Merger Subsidiary ~~will~~would be merged with and into New NPI 4, with New NPI 4 as the surviving entity. On December 19, 2011, NPI 4, AIMCO OP and the Merger Subsidiary entered into an Amended and Restated Agreement and Plan of Conversion and Merger (the “Amended and Restated Merger Agreement”). Pursuant to the terms of the Amended and Restated Merger Agreement, the cash consideration that holders of units of limited partnership interest (each, a “Unit”) of NPI 4 may elect to receive upon consummation of the merger transaction decreased from $195.27 to $167.15, and the number of partnership common units of AIMCO OP that holders of the Units may elect to receive upon consummation of the merger will be calculated by dividing $167.15 by the average closing price of Apartment Investment and Management Company common stock, as reported on the New York Stock Exchange, over the ten consecutive trading days ending on the second trading day immediately prior to the effective time of the merger. This decrease in consideration is due to changes in NPI 4’s financial position and changes in the market value of its indebtedness. Prior to consummation of the transactions contemplated by the Amended and Restated Merger Agreement, the partnership agreement of NPI 4 will be amended to eliminate the prohibition on transactions between NPI 4, on the one hand, and its general partner and its affiliates, on the other.

InThe ~~the~~foregoing ~~conversion~~summary ~~and merger, each unit~~ of ~~limited partnership interest (each, a “Unit”) of NPI 4 outstanding immediately prior to~~ the ~~consummation~~Amended ~~of the conversion~~ and ~~merger~~Restated will be converted into an identical unit of limited partnership interest in New NPI 4 (also known as a “Unit”), following which each Unit (other than Units held by limited partners who perfect their appraisal rights pursuant to the Merger Agreement) ~~will~~is bequalified ~~converted into the right to receive, at the election of the limited partner, either (i) $195.27~~ in ~~cash~~its ~~(the~~entirety ~~“Cash Consideration”) or (ii) a number of partnership common units of AIMCO OP calculated~~ by ~~dividing~~reference ~~$195.27~~to by the ~~average~~Amended ~~closing price of Apartment Investment~~ and ~~Management~~Restated ~~Company~~Merger ~~common stock~~Agreement, as reported on the New York Stock Exchange, over the ten consecutive trading days ending on the second trading day immediately prior to the effective time of the merger (the “OP Unit Consideration”). However, if AIMCO OP determines that the law of the state or other jurisdiction in which ais ~~limited~~attached ~~partner resides~~hereto ~~would~~as prohibit the issuance of partnership common units of AIMCO OP in that state or other jurisdiction (or that registration or qualification in that state or jurisdiction would be prohibitively costly), then such limited partner will only be entitled to receive the Cash Consideration for each UnitExhibit 10.1 ~~Those~~and ~~limited~~incorporated ~~partners~~herein ~~who~~by ~~do not make an election will be deemed to have elected to receive the Cash Consideration~~reference.

In the merger, AIMCO OP’s membership interest in the Aimco Subsidiary will be converted into Units of New NPI 4. As a result, after the merger, AIMCO OP will be the sole limited partner of New NPI 4, holding all outstanding Units. NPI Equity Investments, Inc. will continue to be the general partner of New NPI 4 after the conversion and merger, and NPI 4’s partnership agreement in effect immediately prior to the conversion and merger will be the partnership agreement of New NPI after the conversion and merger and will be amended to reflect the conversion and merger.

Completion of the conversion and merger is subject to certain conditions, including approval by a majority in interest of the limited partners holding Units. As of July 21, 2011, NPI 4 had issued and outstanding 60,005 Units, and AIMCO OP and its affiliates owned 47,850 of those Units, or approximately 79.74% of the number of outstanding Units. Of these 47,850 Units, 21,384 are subject to a voting restriction, which requires such Units to be voted in proportion to the votes cast with respect to the Units not subject to this restriction, which will result in AIMCO OP and its affiliates voting a total of 38,258 Units, or approximately 63.76% of the outstanding Units. AIMCO OP and its affiliates have indicated that they intend to take action by written consent to approve the merger.

The foregoing summary of the Merger Agreement is qualified in its entirety by reference to the Merger Agreement, which is attached hereto as Exhibit 10.2 and incorporated herein by reference.

Additional Information for Investors:

This communication does not constitute an offer to sell or the solicitation of an offer to buy ~~any~~ any securities. AIMCO OP and Apartment Investment and Management Company ~~will~~have ~~file~~filed with the Securities and Exchange Commission a registration statement on Form S-4 that ~~will~~includes ~~include~~ an information statement of NPI 4 relating to the transactions, which ~~will~~ also constitutes ~~constitute~~ a prospectus of AIMCO OP and Apartment Investment and Management Company. INVESTORS ARE URGED TO READ THE INFORMATION STATEMENT/PROSPECTUS ~~WHEN IT BECOMES AVAILABLE~~ BECAUSE IT ~~WILL~~CONTAINS ~~CONTAIN~~ IMPORTANT INFORMATION REGARDING THE TRANSACTION.

The information statement/prospectus and other documents which have been and will be filed with the Securities and Exchange Commission are ~~will be~~ available free of charge at the SEC’s website, www.sec.gov. You may request a copy of these filings, at no cost, by writing or calling Apartment Investment and Management Company at the following address and telephone number: ISTC Corporation, P.O. Box 2347, Greenville, South Carolina 29602; telephone number (864) 239-1029.

ITEM 9.01. Financial Statements and Exhibits.

(d) The following exhibits are filed with this report:

Exhibit
ExhibitNumber		Description
Number		Description
10.1		Amended and Restated Agreement and Plan of Conversion and Merger, dated as of December 19, 2011, by and among National Property Investors 4, AIMCO Properties, L.P. and AIMCO NPI 4 Merger Sub LLC.
10.2		Agreement and Plan of Conversion and Merger, dated July 28, 2011, by and among National Property Investors 4, AIMCO Properties, L.P. and AIMCO NPI 4 Merger Sub LLC.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	~~NATIONAL PROPERTY INVESTORS 4~~		NATIONAL PROPERTY INVESTORS 4
Date: July 28, 2011	By:	NPI EQUITY INVESTMENTS, INC.,
Date: December 19, 2011			By:	NPI EQUITY INVESTMENTS, INC.,
		~~Its General Partner~~		Its General Partner
	~~By:~~	~~/s/ Stephen B. Waters~~	By:	/s/ Stephen B. Waters
		~~Stephen B. Waters~~		Stephen B. Waters
		~~Senior Director of Partnership Accounting~~		Senior Director of Partnership Accounting

[Signature Page —– NPI 4 —- Form 8-K]

Filing Compare · NATIONAL PROPERTY INVESTORS 4